4/8/09 7:39 PM

← Pharmokinetics – speed of drugs through a system thus alleviating

symptoms. Slow (oral & topical). Moderate (intraparenteral – abdominal

cavity & mucosal absorption & intravenous) Fast (intraventricular – into the

ventricles & Intrathecal –injected into the space)

←← Timothy Leary, Ph.D. gave us the laws of effect. The dose, setting

(the stress or environment during study), and set (genetic makeup, eating

and sleeping habits, pH, ect any physiological variables), in order to adjust

the Effect.

←← Neuro pharmacology

← Determination of drug absorption -

← pH and pKa interact to determine the site of absorption.

← Only non-ionized ligands cross lipid barriers redily

← pKa = equilibrium constant

← pKa = pH at which a ligand is nonionized.

← PCP pka = 9.4

← The stomach has a pH of 1.4 and the ph of duodenum = 8.4 (pH) thus

it is more active in the duodenum and enters the blood stream = 7.4 (pH)

←← Plasma protein binding

← Only unbound drug diffuses from the vascular compartment

← Plasma binding protein (eg serum albumin) and free drugs bind to the

protein. “Nonspecific” binding (ie protein indiscriminately binds multiple

ligands.) The binding event doesn’t have any change of the activity of the

proteins – worthless activity for the desired effects of the drugs taken.

Plasma drug binding is almost 99% absorbed by plasma binding proteins so

only a few % end up entering your system for functionality. Look at the

formula!!

←← Fluid “compartments” determine distribution, concentration.

← If a drug is taken orally will enter the blood plasma/circulatory system

(determined from the pKa). The circulatory system needs to enter the blood

brain barrier in order to become active. Remember that most of the drug is

bound to plasma proteins and wasted! There is no conductors/tickets only

the statistical ability. Since most proteins are highly charged and large so

they can pass to the circulatory system. The liver, kidneys, heart, skin, ect

are all possible enterance sites. These might have fatty tissues (adipose)

where the drugs can trapped. Circulatory system passes through the liver

for metabolizing or the kidneys for excretion. Only a very small fraction of

the drugs are actually reaching the brain. Remember Effects and Side-

effects.

←← The BBB (Blood-Brain Barrier)

← Peripheral blood vessels have fairly loose junctions between the cells

(porous). Some substances can pass through these gap junctions. If the gap

junctions were too large you would loose blood plasma and die so these

junctions must be small. The CNS blood vessel have tight junctions. There

are multiple membranes to cross and glial cells (astrocytes) have two more

sets of membranes (total 6 membranes to pass through vs only two in the

peripheral blood vessels. The drugs must be able to be passed to and from

the brain.

←← Metabolism of Drugs – transformation of drugs from one state to

another

← Hydrolysis

← Oxidation

← Conjugation

← all via enzyme activity

←← Metabolism + Excretion = Drug Clearance

← Log plasma concentration (ng/dl) vs time (hr) graph has a negative

slope. The clearance time (lifespan of drug in system) from the highest

concentration to zero. The time to reach the halfway point between the

highest concentration to zero is the half-life of the drug. *notice the half-

time is the is going from one value (not the highest value) to half of that

value*

←← Attaining steady state concentration

← Concentration vs Time (multiples of elimination half times)

← Time to Steady State

← - attained after approximately 4 half-times

← - Time to steady state independence of dosage

← Steady State Concentrations

← - proportional to dose/dosage interval

← - Proportional to F/CL

← Fluctuations

← - Proportional to dosage interval/half time

← - Blunted by slow absorption

←← Developmental regulation of drug clearance

← Graph Clearance vs. Age

← Before 0-1 you steadily go to the highest clearance until puberty and

then there is a downward slope. Be careful to give drugs to very young and

very old because they aren’t able to clear drugs out of their system as

quickly.

←← Dose-response relationships

← Efficacy – look at graphs in book

← Kd is the concentration of 50% of the full effect (Bmax)

← Log of drug concentrations can give you a sigmoid curve.

← For each drug you can determin the potency by looking at the

concentration of drug… if it doesn’t take as much to reach the Kd then it is

more potent. The more efficacy of the drug would be the sigmoid

← Potency is how much to use to get the same effect (maximal effect)

← Efficacy is how well the drug works

←← Agonist vs Partial Agonist

← A full agonist is a drug that can fully activate a mechanism (complete

efficacy)

← A partial agonist can only partly activate a mechanism (partial efficacy)

← The potency of the partial agonist may be more potent (require less

drug) than a full agonist. *remember potency and efficacy are different!

←← Therapeutic index: LD50 vs. ED50

← The graph is the % of individuals responding vs. dose (mg)

← LD = lethal dose; LD50 is the dose to kill 50% of the population at that

dose

← ED = effective dose; ED50 is similar to LD50.

← The ED50 is much lower than the LD50. The therapeutic index is the

LD50 divided by ED50. There are over lapping information. What might be a

ED99 might be LD2. The approval of a drug depends on the therapeutic

index of at least 10.

←← Issues with repeated drug treatment

← Graph Intensity of effect vs. tolerance.

← Initial response may be higher than the second time, this is called

Desensitization (habituation). Recovery may also happen when the user

stops taking a drug for a period of time, and the intensity of effect may rise

to normal (initial response). The recovery can be hazardous because a

patient may take a higher dose thinking that

←← 1/20/09 – was 15 minutes late

← Peripheral vs. CNS

← Evoked mEPPs (mV) *NMJ & Spontaneous mESPs (mV) *CNS

←← Presynaptic Ca2+ channels are anchored to membrane binding

proteins (SNARE = Soluble NSF Attachment REceptor)

←← enhanced [Ca] 1-3x10^-4)

← VDCC and SNAREs are attached to the presynaptic membrane are

close together. The other SNAREs are attached to the vesicle and they

become closer together until the vesicle fuses to the presynaptic membrane.

Similar to the actin and myosin sliding but this causes the fusion.

←← EM shows vesicular docking

← -transmission EM of CA1 neuron synaptic transmitter release

← - Cs+2 mediated interactions of SNARE proteins resulting in vesicular

fusion

←← Vesicle associated membrane proteins (VAMPs)

← There are many different types – **synapsin, synaptobrevin, &

synaptotagmin*primary ones but there are dozens of others.

←← Vesicular fusion, and after

← NSF = N-ethymaldeimide sensitive fusion protein (ATP-ase)

← Each VAMPs have different SNAREs . The voltage dependant Ca2+

channels allow Ca into the cell activating the ATPase functionality and the

coupling of SNAREs and VAMPs is possible. Fusion of the vesicle and the

presynaptic memebrane is complete.

←← BoTOx block of presynaptic vesicular release

← Then botox is added there is no fusion of the VAMPs and SNAREs by

changing their shape. Changing the shape will cause a loss in binding to the

presynaptic membrane thus there will not be a release of NT. An increase in

the concentration of botox, they epsp will decrease incrementally until some

little excitation won’t by affective postsynaptically.

←← Presynaptic exocytoxins block fusion

← Toxin

← Clostridial Toxins

← - botulinum toxins (botox)

← - tetanus toxin

←← EM of fusion

← Scanning EM of freeze fractured presynaptic membrane unstimulated

and after depolarization (pits and omega profiles present)

←← Endocytosis

← Clathrin attached to microtubles interact with synaptotagmin for

endocytosis. Still triggered by ATPases

←← Evidence for and models of membrane recycling

← Classical model – medium time

← Kiss and run model – short time

← Bulk endocytosis model – longer time

←← Vesicular Membrane Cycling

← NTs are being pumped into the vesicle via aid of VAMPs (filled with one

quanta). The transportation and docking occur near a Ca2+ channel with

the aid of ATP. Priming and fusion (exocytosis) due to the depolarization and

sliding of the SNARE and VAMP interaction and Ca2+ concentration increase.

ATP binds the Cathrin to the VAMPs and endocytosis happens. Protons are

being pumped into the vesicle bringing the pH of the vesicle to the lower.

The endoplasmic reticulum may be included in the loop or not. The acidicy

of the interior of the vesicle aids in the NTs to be pumped back into the

vesicle and loop begins over.

←← Depolariaztion, CA2+ influx, vesicle fusion, release, Na+ influx

← 1. Ca2+ influx via presynaptic voltage dependant Ca+2 channels

← 2. Membrane proteins and VAMPS fuses vesicle to membrane

← 3. Release NT binds to gates postsynaptic receptors

←← Rapid NT clearance from the synapse

← 500 microseconds to have the clearance of the whole event.

←← 1/22/09

Post synaptic information

Receptor-effector coupling – ligands bind to receptors and then the effector

on the intracellular domain. Most receptors are bound to the lipid bilayer but

not always true. Some channels are ion channels (ionotropic) and some do

not (mechanotropic).

Stochastic nature of equilibrium binding

- ligands (L) and receptors (R) vary in number in different areas. Some

molecules of the ligand come close enough to the receptor. Over a

certain amount of time there should be a number of ligands binding to the

receptors. As time continues, free ligand molecules (F). Once they

associates there is a value Ka – the rate of free ligands binding to

receptors to form a ligand/receptor complex (or # of bound complexes

(B)).

- [L] = [F] + [LR]

- [LR] = [B]

- The whole reaction is a two way reaction until equilibrium is reached. A

ratio is expressed. To know the dissociation constant (Kd) you must know

the Kd = [F]*[R]/[B]. You use this information to determine the affinity of

drugs. The affinity is measured by using 1/Kd. Bmax = [R] + [B].

Defining classes of ligands

- agonist: binds to and activates effector site

full agonist; maximally activates effector

partial agonist; only partially activates effector

inverse agonist; reverses effector mechanism

← - antagonist: does not activate effector site

competitive; binds to effector site

noncompetitive; binds to site distant from effector site

suicide; binds irreversibly

← - modulator: alters affinity or efficacy

affinity; binding “attraction” of ligand and of receptor

efficacy; maximal effect obtainable

←← Multiple competitive types I, II, III

← Non-competitive antagonism – there are multiple sites on receptor

← All sites open: receptor inactive

← Agonist site occupied: receptor active

← Agonist site open: receptor inactive

← Antagonist site occupied: receptor inactive

←← Plasticity 1: experience-dependent shifts in dose-response curves

← Plasticity 2: antagonists shift dose-response curves

The increase in competitive antagonist will shift the agonist curve to

the right which looks like tolerance.

If a noncompetitive antagonist will reduce the maximal affect

achieved. It doesn’t change the ability of the agonist to bind but

the number of receptors useful.

←← Common pharmacological analyses

← Dose-response curves

The efficacy and potency of ligands

← Inhibitor plots (antagonist)

Track efficacy, potency of antagonists

← Hill plots

Calculate # of binding sites/receptors

← Time-dependent (kinetic) plots

Association (binding)

Dissociation (unbinding)

Clearance (half-life and half-time)

← Scatchard plots

Calculate kinetic variables

← Saturation curves

Calculate binding capacity

←← Hill coefficient = binding sites/receptor

← The number of binding sites of the receptor determined by the slope of

the effect (nA)/log [ACh] (nM). A higher hill coefficient will determine the

amount of NT needed to activate a receptor.

←← Saturation curves – specific vs. nonspecific binding

← Y axis – amount bound (fmol/mg protein)

← X axis – [Ligand] (nM)

← Specific = total – nonspecific

←← Scatchard plot: ratio of B to F ligand at equilibrium

← Y axis = log [B]/log [F]

← X axis = log [F]

← The slope = 1/Kd

← X-Intercept = Bmax

←← 1/27/09 – 5 min late

← 3 major G=protein families: Gs, Gi, Gq

← Gs – increases AC activity

← Gi – decreases AC activity

← - increase PLC activity

← Gq – increase PLC activity

← G-protein = guanosine-phosphate-binding protein

←← Both alpha and Beta-gamma subunits can be active messengers. But

the alpha subunit is the diffusible subunit and the Beta-gamma subunit is

membrane bound so the activity of the subunit is limited (sorta).

←← Life-cycle of G-protein effector coupling

← The alpha and beta-gamma subunits are bound together and the alpha

is bound to GDP. The ligand receptor complex forms when the ligand binds

to the receptor. Once the complex forms the affinity for the G-protein and it

interacts with the ligand receptor complex. The GTPase adds or converts the

GDP into a GTP. The GTP is bound to the alpha subunit/beta-gamma subunit

is now has higher energy (unstable). The alpha-GTP dissociates from the G-

protein complex and can act as a source of phosphates (adding energy to

rxns). The beta-gamma subunit now can also act as a secondary messenger.

Again a GTPase converts the GTP into GDP again, either by transferring the

phosphate to another molecule. The alpha-GDP and beta-gamma subunits of

the Gprotein can now associate once more and the ligand is release from the

receptor.

←← Small G-proteins

← Look at GAPS and GEFS in book. Pg. 80

←← Hydrolyzable and non-activating forms of GTP

← GTP can by hydrolyzed

← GTPgammaS – toxic effect because the GTP will not be able to be

removed from the active alpha subunit of G proteins.

←← Alpha subunits and toxins

← Cholera toxin *diarrhea (attacks alpha-s subunits)

← Pertussis toxin *whooping cough (attacks the alpha-I and alpha-o)

←← Enzyme terminology

←← Multiple pathways, diverging and converging

←← 1/29/09

← Second messenger

← A messenger is something that carries message.

← Messenger cascades. The book says that any the second messenger is

the molecule that transmits the “signal” after the g-protein.

←← Enzymes transiently disrupt homeostasis

← - cyclases (eg AC) vs. phosphodiesterases (PDEs)

← - synthases (eg NOS, etc.) vs. proteases, lipases (egPLC)

← - kinases *adding phosphate groups (eg. PKA, PKC, CAM-KII) vs.

phophatases *removes phosphate groups (PP1, calcineurin)

←← Cyclases produce cyclic nucleotides

← ATP is converted into camp via adenylyl cyclase (aka AC & is

membrane bound with two catalytic sites.) **important in Gs and Gi

gproteins.

← Guanylyl cyclase has only one catalytic domain but has the ability to

be unbound.

←← Gs, calmodulin (CAM) and forskolin activate AC

← G-protein alpha subunits activate or inhibit cyclases

← CAM is endogenous calcium binding protein(CBP) that can bind 4 Ca

ions; forskolin is a plant-derived organic toxin; many other pathways also

converge on AC.

← High levels of intercellular Ca will activate the adenylyl cyclase. Gi and

Go decrease the amount activity of AC

←← cAMP-dependent protein kinase (PKA)← Binding 2 molecules of cAMP to each of the 2 regulatory subunits of PKA releases the

2 catalytic subunits. See pg 92 in text. ** there needs to be 4 cAMP in order to fully release

the active subunits.

←

← 7 classes of phosphodiesterases (PDEs) ** just know that there are

seven and the major difference between them is the affinity of their

substrates are – either cAMP or cGMP creating 5’cAMP and 5’cGMP

respectively.

←← NO synthase (NOS) produces NO

← L-arginine is converted into L-citrulline + nitric oxide (NO)via NOS + a

cofactor of Ca. NOS activity is also regulated by CAM.

←← NO is a retrograde neurotransmitter

← NO activates presynaptic guanalyly cyclase which increases the cGMP

production which increases the vesicle binding to the presynaptic

membrane; increased presynaptic cGMP increases vesicular transport rate.

←← Phosphotidylinositol (PI) metabolism

← The main component of the pathway is the PIP2. Li can interfere with

the metabolism of PI. It is a cyclic pathway

←← PLC is activated by Gp or Go alpha subunits

← PIP2 is cleaved into 2 fragments by PLC:

DAG (membrane bound)

IP3 (diffusible)

← PIP2 is the substrate and the PLC acts as the enzyme to form DAG and

IP3

←← PKC is activated by free Ca and by DAG. The enzyme has a restrictive

and catalytic sites. When in the inactive form Ca and DAG form the active

form of the PKC. Since binding of DAG to the catalytic subunit is required for

activation, most forms of active PKC are membrane bound.

←← IP3 activates and intracellular IP3 receptor. The IP3 receptor

(ionotropic receptor) releases Ca sequestered within the smooth ER (an

intracellular Ca store). The Ca is sequested via a ATP pump (ATPase) and

during the reaction the Ca is used & stored inside the smooth ER.

←

← IP3 and ryanodine receptors activate Ca channels – both release Ca

from intracellular stores. Both muscles and neurons have IP3 and ryanodine

receptors. IP3 receptors are activated by IP3 but Ryanodine receptors cause

Ca to be released by ryanodine and Ca (positive feedback).

Thapsigargin – blocks the ATP pump into the smooth ER store.

Calsequestrin - (Ca binding protein) thus it gets stuck inside the

smooth ER.

←← CAM, calcineurin, and CAM-KII

← Autophosphoylation of CAM-KII happens immediately after the active

state is reached by the binding of high levels of CA/CAM and is locked in the

active state. Calcineurin has binding sites for Ca and CaM. Binding of Ca has

little affect of activity but binding of both, CaM and Ca will greatly increase

the activity. ** remembrer CAM needs Ca to be bound to it to be active**

←← Intracellular stores are one of the many intracellular free Ca sources.

Channels are sources of Ca while pumps and exhcnagers & CBP are sinks.

← Voltage Dependant Ca Channels. ATPases pump Ca outside the cell

and Na+/Ca2+ exchangers are also used where 3Na+ are pumped inside the

cell and one Ca2+ is pumped out. ** most Ca pumped outside would be

through the ATPase pump but it costs energy but the Na+/Ca2+ will

eventually cause the cell to depolarize. Ca is very important in regulation***

←← 2/3/09

← Review for test at 6pm today

←← Cyclase pathways – Adenylyl Cyclase is stimulated by Gs and inhibited

by Gi. ATP is the substrate to make cyclic AMP. Ion channels can be opened

or other processes such as increasing Ca ion

←← CAMP and Phosphodiesterases (PDEs) use cyclic nucleotides (cAMP or

cGMP) 5’cAMP or 5’cGMP.

←← IP3 receptor and products.

← Ca+2 binding proteins (CaBPs)

o Calmodulin (CaM)

o PKC

o Calsequestrin

o Calcineurin

o Calbindin

o Parvalbumin (found in inhibitory interneurons)

← Organic Ca2+ chelators

o BAPTA

o EGTA

←← Dentritic spine apparatus – limits the amount of Ca allowed localized

by the synapse.

←← PKC and CAM-KII

← PKC is activated by Ca+2 and DAG

← CAM-KII is activated by Ca+2/CAM and autophosphorylates itself in

order to remain active even when [Ca] lower.

←← Serine/threonine phosphateases

PP1

o Catalytic + target subunits/inhibitors

o Regulation

PI1

o Inhibitors

Okadaic acid & DARPP-32

PP2A

o Heterotrimer (catalytic + 2 regulatory)

o Regulation

Ceramide, phosphorylation, methylation

o Inhibitors

Okadaic acid

PP2B (calcineurin)

o Heterodimer (catalytic + CAM binding site, CAM-mimic)

o Regulatation

CA2+ / CAM

o Inhibitors

Cyclosporin, cyclophilin, pyrethroids (insect) FK506 Fepb

PP2C

o Catalytic subunit

Phosphatase Inhibitors

Okadaic acid inhibits PP1 and PP-2A

Deltamethrin inhibits calcineurin

Cyclosporin inhibits calcineurin

PHosphatase regulation: DARPP-32 (dopamine and cAMP regulated

phosphoprotein)

Phosphorylated DARPP-32 inhibits PP1, therefore provides positive feedback

for AC activation.

←

←←←←

4/8/09 7:39 PM

← Ion Channels: Depolarizing

← Ionophores: non-gated channels

← Toxins

Monensin

o Source – Bacteria

o Mechanism of Action

Macro – antibiotic

Micro – Na+ ionophore

Amphotericin

o Source Strepococcus

o Mechanism of Action

Macro – antifungal and antiprotozoal

Micro – NA+/K+ ionophore

←← ATPases (pumps) can change membrane polarization

Na+/K+-ATPase

o For every 3 Na+ pumped out, 2 K+ ions enter the cell;

causing a hyperpolarization.

←← Pump toxins disrupt function

← Toxins

Digitalis

o Blocks NA+/K+ ATPase by inhibiting dephosphorylation

Ouabain (wabain)

o Blocks NA+/K+ ATPase

Thrapsigargin

o Blocks Ca2+ATPase in ER

Depolarizing channels

Voltage-gated

o Na+ channels

o Ca+2 channels

←← Gating Models

*Regional conformational change – a selective portion of the protein

structure changes

General conformational change – entire structure changes

*Blocking particle

← * most likely to be the cause

←← Three kinetic steps

Open inactivation closed

The inactivation gate (msec) will be much slower than the activation

gate (nsec)

←← Voltage-clamp single-channel recording

The voltage would rise during the Voltage command step

The current opens during the command step and it shuts off but the

voltage still remains depolarized.

←← Active, inactive and closed

In the inactive state there is no current but the voltage still remains

depolarized.

←← Cahnnel structure conservation

← Na and K channels end up being made up of a single protein. There is

an open central space. There are inactive regions and active regions within

the protein.

←← Visualizing Na channels

← 4 subunits with 6 transmembrane segments each

← Na channel types NaV1.x don’t need to know

←← Local anesthetics block Na+ channels

Cocaine

Lidocaine widely used because of less cardiac and liver toxicity

←← TTX block Na+ channel conductance

Fugu fish (sushi)

←

← Additional Na+ channel blockers

← Toxin

Saxitoxin (STX) red tide

Tetrodotoxin (TTX)

QX-314 works from the inside, used in recording electrode to

selectively turn off neurons individually

←← Cardiostimulants prevent inactivation of Na+ currents

Aconitine – monks hood

Veratridine – rhizomes of sabadilla lily

← * both are considered neurotoxins but may be used for very low heart

rates

←← Intracellular Ca2+ channels

IP3 (neurons and muscles)

o IP3 is the agonsist

o Heparin (blood thinning agent) and caffeine are antagonists

Ryanodine (skeletal muscle, cardiac muscle, neuronal)

o Ryanodine, caffeine, and heparin are all agonists

o Dantrolene is the antagonists

←← Ca2+ channel subunit structure

← 4 subunits with 6 transmembrane domains each

←← Two major types of Ca2+ channels

LVA (low-voltage activated)

o Rapidly inactivating

HVA (high-voltage activated)

o Inactivating

o Noninactivating

←← 2/12/09

← Voltage-dependent Ca2+ channel (VDCC) types

← L

Found in neuronal (CaV1.2-1.4) and muscle (CaV1.1) cells

HVA & noninactivating

Blocked by inorganic ions (cobalt, cadmium)

← T (transient)

Cardiac, Nuronal (CaV3.1-3.3)

LVA and Fast Inactivating

← N

Neuronal only (CaV2.2)

HVA and Slow Inactivating

← P/Q (purkinje) and originally thought to be presynaptic but also in

postsynaptic

Neuronal only (CaV2.1)

HVA and Slow Inactivating (but not as slow as N type)

← R (found originally in retina)

Neuronal Only (CaV2.3)

HVA and Fast Inactivating

←← Organic Ca2+ channel toxin sources

Spiders, snakes, tree roots, and microorganisms

←← Ca2+ channel Ligands I

← Blocks L types

Dihydropyridine

o Nifedipine – widely used for hypertension to regulate heart

rate and cardiac output

o Nimodipine – Brain specific

Arylalkylamine

o Verapomil

Benzothiazepine

o Diltiazem

Alkaloids

o Phloretin (plumb tree roots)

← Blocks T type

Benzimidazole

o Flunarazine

o Mibefradil

← Blocks N type

Conotoxin peptides

o Ω-CTX-GVIA (conotoxin gene 6 A)

← Blocks N, P/Q

Conotoxin peptides

o Ω-CTX-MVIIC

←← Ca2+ channel ligands II

← Enhances L type

BAY-K-8644

← Enhances ALL types

Maitotoxin

← Blocks P/Q (funnel spider toxin)

Omega-Aga-Ia

← Blocks L type

Phloretin (fruit tree root alkaloid

Blocks ALL types

Inorganic ions (Mg2+, Cd2+, Cs2+, Ni2+, Co2+)

← ** barium flows through Ca2+ channels better than Ca2+

←← Ca2+ homeostasis in neurons

← Ca2+ Influx

VDCCs

NRs (NMDA receptors)

Na+/Ca2+ exhanger

← Ca2+ stores

CaBPs

ER

Mitochondria

← Ca2+ release

IP3Rs

RyRs

Ca2+ dependent

Ca2+ release

← Ca2+ Efflux

ATP-ases

NA+/Ca2+ exchanger

←← Ca2+ imaging with fluorescent indicators

Fura 2 most commonly used

←← Voltage-Gated Channels: Hyperpolarizing

Chloride (Cl-) channels

Potassium (K+) channels (K channels can flow inward if the cell is

above than the resting potential or outward if the cell is below the

resting potential voltage -65mV.

←← Chloride Channel Toxins

Chlorotoxin

Flufenamate (chlorea use)

Tamoxifen (breast cancer treatment)

←← K+ Channel toxin sources – organic and synthetic

←← 4 major classes of K+ channels

Voltage-Dependent K+ channels (VDKC)

o Ia (first observed),

o Id (delayed),

o Ik,

o Im (muscurine sensitive)

Rectifier (making right returning to right potential) K+ channels

o Ik,

o anomalous rectifier (activated by below resting potential),

o Ih(queer) – hyperpolarization activated

o tandem pore – form two channels per molecule

Metabotropic-Gated K+ channels

o Im (metabotropic regulated)

o ATPsensitive (requires ATP)

o Iahp (After hyperpolarization potential)

Ca2+-dependent K+ channels (CDKC)

o Ic (calcium)

o Im

o Iahp

←← 2/17/09

← VDKC structure (Ia, Id, Ik)

4 separate subunits with 6 transmembrane segments each

←←← K+ currents and action potential firing

← Ia and Id are the first to be activated and try to keep the action

potential back to resting. As the voltate rises up then the delayed rectifier Ik

and brings the resting potential. Then Ca dependant K channels are

activated . Then the Ic, Im, Iahp to lower the after hyperoplarization

potential. Then the slowIAHP, and ISahp. These determine ability for a neuon

to fire again. If we reduce the capacity for the Ic, Im, Iahp, I ahp, & Isahp.

←← VDKCs (see notes)

← Ia

LVA and Fast inactiating

Blockers – DTX (dendrotoxin)

Id

LVA

Some rectifier K chaneels structures are add

Anomalous: 4 separate subunits with 2 transmembarne segments each

Tandem Pore: 4 transmembrane segments eac, dimerize for 2 pores VIA

volatile anesthetics

Ik

Activation – HVA

Inactivating – SI

Blockers – Cs+

Tandem pore

Activation – voltage independant

Inactivating – SI

Activators

o Halothane

o Isoflurane

Blockers – none known

← Anomolous rectifier (inward rectiviers)

Activation – HA (hyperpolarization activated)

Inactivating – SI

Blockers – CS+

← Ih

Activation – HA (hyperpolarization activated)

Inactivating – SI

Blockers – Cs+

←← Metabotropic-Gated channels

← Im

Channel proteins KCNA1-5

Ca2+ sensitivity- High

Neurotransmitter sensitivity – Muscarinic Ach agonist

Activation - LVA

Inactivation - NI

Activators - retigabine

Blockers – linopirdine, muscarinic agonist

← Iatp

Channel proteins – Kir6.x

Ca2+ sensitivity - insensitive

Neurotransmitter sensitivity - ATP

Activation - None

Inactivation - NI

Activators – ninoxidil (blocks conversion of testosterone to dht)

Blockers – ATP

← Iahp

Channel proteins – 2 or more families

Ca2+ sensitivity – high

Neurotransmitter sensitivity – NE, DA, 5HT, Glu

Activation

Inactivation

Activators

Blockers

←← CAM and SK-channels

CAM remains constitutively bound to SK channels, acting as their

Ca2+ sensor

Apamin (bee venom) binding to SK channel

←← CDKCs

← Im

Channel proteins

Ca2+ sensitivity - low

Neurotransmitter sensitivity - NO

Activation

Inactivation - SI

Activators - retigabine

Blockers – linopirdine

← Ic

Channel proteins - BK

Ca2+ sensitivity - >1uM

Neurotransmitter sensitivity - Yes

Activation

Inactivation - SI

Activators - Niflumate

Blockers – charybdotoxin & TEA (uM)

← Iahp

Channel proteins - SK

Ca2+ sensitivity – 200-600nM (CAM)

Neurotransmitter sensitivity - No

Activation

Inactivation - NI

Activators

Blockers – apamin, dequalinium, neurotransmitters

← IsAHP

Channel proteins - ???

Ca2+ sensitivity

Neurotransmitter sensitivity - no

Activation

Inactivation - NI

Activators

Blockers – neurotransmitters – via PKA PKC and CAMKII

metabotropic pathways

←← Comparing CDKCs – The last three are the AHP portion of the neuronal

firing

←← 2/19/09

← Glutamate receptors

← Ligand gated Rs: non-NMDA-rs

← Ionotropic neurotransmission – cell neighboring another cell that fires

can also have an excitatory post synaptic potentials. Glutamate is the

neurotransmitter that brings about EPSPs (Glu for short). Inhibitory (IPSPs)

are GABA modulated. EPSP depolarize and IPSP hyperpolarize. They are not

separate from each other but sum. The sum of the two identical units of

stimulation from both EPSP and IPSP is still an inhibition not an excitation!

You need a larger amount of excitation than inhibition (they are not linear

function).

←← Excitatory amino acids

← Glu

← AMPA

← KA

← NMDA

←← Defining GluRs by regional ligand binding

← AMPA the most abundant receptor type in nervous systems

← Defining GluRs by effector mechanisms

AMPA is part of the receptors for Sodium (Na+) channels

← Protein Homology (genes also)

← AMPARs

Glu R1-R4

← KARs

Glur5- glur7

KA-1 & KA-2

← Defining GluRs by gene expression

←← GluRs subunits form tetramers

← AMPARs typically contain at least one GluR2, at least one other

subtype, thus act as Na+ channels (hill coefficient = 2)

←← GluR biology: unique GluR2 subunits. Amino terminals on exterior and

carboxyl group in the cytosol. There are 4 membrane spaning and a subunit

Q/R site where you can either have a Q = Gln or R = Asp. That area

determines the specificity for Na+ if not then they will also allow Ca2+ ions

through also. The flip-flop site where alternative splicing determines

polyamine sensitivity. The sensitivity will increase the amount of Na+ influx

under the right conditions.

←← Agonist

AMPA – best activator of receptors (but exogenous)

Glu (endogenous)

← Antagonist (all competitive)

NBQX (blocks AMPA receptors)

CNZX (block KA receptors

← AMPAkines (inc. affinity of AMPARs for Glu)

Aniracetam (enhances Glu binding to receptors)

←← KAR ligands

← Agonist

KA (best activator or receptors

Glu

← Antagonist (all competitive)

CNQX

←← Receptor desensitization

← Receptor – AMPA ; cyclothiazide removes desensitization

← Receptor – KA ; concavilin A (conA) removes desensitization epilepsy

possibilities

←← Iontropic effects of Glu

← AMPA receptors and NMDA receptors. An EPSP (voltage) and EPSC

(current (mA)) create an action potential.

←← Glu EPSPs are typically mediated by multiple receptor types.

←← Glu: multicomponent EPSCs See notes

←← Sulfur-containing EAA transmitters

← Homocysteic acid – produced an anoxious state drownding and

taurine does not cross the blood brain barrier but in diseased states then it

stimulates the inhibitory function.

←← 2/24/09

← Glutamate

← Defining NMDARs by gene expression

← Ionotropic NMDA, AMPA, Kainate (functional classes)

← NMDA gene families (NR1, NR2a-d, NR3a &b)

← Typical NR = 2 NR1 + 2 NR2 subunits

←← NR subunit expression varies regionally

← NR1 are found everywhere in the brain

← NR2a – d are regionally distributed

← Ex: RN2a are found in hypocampus & Nr2c – cerebellum

←← Unique protein structure of NRs – NR= 2 NR1, 2 NR2 (dual-heterodimer

= tetramer) The subunits NR2 determine the flow and glutamate binds to

the NR2s. The NR1 have binding sites for glycene (Gly). The receptors have

a co-agonist… it requires all sites activated (2 gly and 2 glu) *unique

←← Functional analysis of NRs (see notes)

←

← Uses/abuses of NMDAR ligands

Therapuetic

o Dissociative anesthesia

o Cough suppression

o Learning and /or memory enhancement

o Stroke/drowning/ischemia neuroprotection

Non-therapuetic

o Dissociative hallucinogen

←← PCP

Antagonist – blocks open channel

o PCP (phencyclidine; angel dust)

o MK-801 (dizocilpine)

o Angeldustin (endogenous)

o Ketamine (veterinary practices)

o Dextromethorphan (robitusin)

o Memantine (memory treatment in Alzheimer’s)

← Mg++

Antagonist – blocks open channel

o Mg++

o Memantine

← EtOH

Antagonist – blocks channel opening

o EtOH (ethanol)

← Polyamine

Antagonist – decrease (ANT) Glu binding affinity

o Ifenprodil

o Cadaverine (endogenous)

Agonist – increase (AGO) Glu binding affinity

o Spermine

← Heavy Metal

Agonists – prolongs open channel

o Zn++

← HPO4-

Agonist – prolongs open channel

o HPO4-

←← “Use-dependent” Mg++ block 1

← When magnesium isn’t present there is a continuous opening but with

normal [Mg++] it will “flicker”

←← NR noncompetitive antagonist impair learning

← PCP people cannot learn very well

←← Regulation of NRs by phosphorylation

← NMDAR is attached to PSD-95 connected to other proteins and mGluR

is bound to the homer, which can cause phosphorylation of the NMDA

receptor and enhances the current flow. Review Hammond…

←← Excitotoxicity via NRs

← NMDA induced apoptosis via Ca++ influx… APV, MK-801, Kyn block

apoptosis

←← NR2 Glu-binding site ligands

Agonists

o NMDA (N-methyl-Daspartate)

o Glu (glutamate) (endogenous)

Antagonist (competitive)

o APV (AP5 = D-amino-phosphovaleric acid) higher affinity

than glutamate but it doesn’t cross the BBB

o CPP (crosses the BBB)

←← NR2 antagonist impair learning

← - adding APV to mice will greatly impair their learning

←← NR1 Gly-binding site ligands

Agonists

o Ser (serine *endogenous via glial cells)

o Gly (glycine *endogenous)

Partial agonists

o DCS (D-cycloserine)

Antagonist (competitive)

o Kynurenate (kyn *endogenous)

←← Gly or Ser as a coagonist of NRs

←← NR roles in plasticity

← Antagonists block learning, and agonists generate seizures

←← 2/26/09

← Inhibitory amino acid receptors – GlyRs, GABAARs, GABACRs

←← 5pm Friday study review.

←← Pentameric receptors (five sets of subunits make up their structure)

← GABA-A – contain alpha and beta subunits (and gama)

← GABA-C – contains rho subunits

←← Structural conservation between inhibitory Rs

←← GlyR anchoring to the cytoskeleton, “clustering”

← They are attached to gepherin to form the clusters and attracted to

microtubules and neurofilaments and other gephrin. If there is a knockout of

the gepherin the GlyRs are not clustered and inhibition is affected.

←← GlyR activated IPSPs (hyperpolarization of the membrane). Activation

of the receptors cause and influx of Cl- ions.

←← GlyR activated IPSCs has a hill coefficient of 2

←← GlyR ligands (strychnine sensitive)

← Agonists (competitive)

Gly

Taurine

← Partial agonists (competitive)

B-aminobutyrate (BABA)

← Antagonists (competitive)

Strychnine (muscle spasms and breathing issues)

← Antagonists (noncompetitive)

Picrotoxin

Picrotoxinin

←← Regional heterogeneity of GABAAR alpha subunits

GABAAR mediated Cl- currents are ligand- and voltage-dependent

GABAAR desensitization – the decrease in reactivity to prolonged stimulation

Nipecotate suppresses but prolongs IPSPs

Uses/abuses of GABAAR ligands

Therapeutic

Sedatives

Hypnotics (sleeping pills)

Anxiolytics

Seizure prevention, reduction (AEDs) Anti-Epileptic Drugs

← Recreational

Date rape

Sedative-hypnotics

Anxiolytics

Agonist Antagonist Allosteric

Modulator

Ligand Competitive Noncompetitive

GABA bicuculline picrotoxin barbiturates

muscimol GABAzine picrotoxinin BDZs

gavozadol -cyphat neurosteroids

isoguvacine flucybene EtOH

propybicyphat

← Related issues:

Development of tolerance

Development of dependence/addiction

Overdose

Side-effects

←← Allosteric modulators effect GABAAR IPSPs

←← Barbiturates enhance Cl- conductance of channel

← Ligands

Agonists (competitive)

o Phenovarbital (luminal) and pentobarbital (nembutal)

←← Benzodiazepines (BDZs) enhance the affinity of GABARs for GABA.

More is likely to bind and stay bound.

← Ligands

Agonist (competitive) – bloth classes of omega receptors

o Chlordiazepoxide

o Diazepam (valium)

o Carbamazephine

Agonist (partial)

o Bretazenil

Antagonists (competitive)

o Flumazenil

Agonists (inverse)

o Carboline

← Omega 1 receptors are associated with hypnotic affects

Zolpidem (ambien) – non-benzodiazepine hypnotic

(imidazopyridine)

Eszopiclone (lunesta) – non-benzodiazepine hypnotic (cyclopyrrone)

← Omega 2 receptors are associated with anxylitic

←← Diazepam liver conversion to nordazepam oxazepam and two

products after breakdown are still BDZs

←

← Neruosteroid Ligands

Agonist (competitive)

o Pregnenolone – decrease anziety and increase GABA affinity

Antagonists (competitive)

o Allopregnanolone – increases anxiety – reduce GABA affinity

←← GABACR are unique (and rare) – found in the retina horizontal cells.

They have long durations and high current.

←← Only common in retinal horizontal neurons

← Pentameric but unique subunit expression : Rho

← Mostly insensitive to most GABAa and GABAb antagonists

← Insensitive to modulators (nosensitivity to BDX/

Barbiturates.neurosteriods/ethanol

← Very slow channel gating (activation inactivation occurs in secs not ms

← Little or no desensitization

← Cl= channel blocked by pirotoxin/picrotoxinin

←← GABACR Ligands

← Agonists (competitive)

GABA

← Agonists (partial)

CACA (cis-4-aminocrotonate)

← Antagonists (competitive)

TPMPA

← Antagonists (non-competitive)

Picrotoxinpicrotoxinin

←3/3/09

nAChR gating via conformational change. They are pentameric and use a

sliding mechanism to change the chape of the channel pore.

Was the 1st receptor purified, sequenced, cloned, imaged via torpedo fish

studies.

There is conserved subunit structure among receptors

The developmental reguation and locale of nAChRs in a child there will be a

gamma and in adults is epsilan. The will have 2 alpha, 1 beta,

nAChR alpha 7 receptors and smoking. An all alpha 7 monomer where all

the 5 subunits are identical.

nAChR mediated Na+ Currents and there is a linear I’V curve

Desensitization by phosphorylation = matabotropic receptor cascades

Uses/abuses of nAChR ligands

Clinical

o Treatment of motor dysfunction

o Treatment of cognitive impairments, ADD

o Treatment of memory impairments

o Weaning from tobacco addiction

o Regulation of autonomic functions

o Induction of surgical paralysis

Non-clinical

o Recreational smoking, chewing, snuff

o Insecticides, neurotoxins

o Paralytic hunting, assassination poisons

←← Short- and long-acting analogs of ACh

← ACh (short) methacholine (medium) carbachol (long)

← Expression ← Neuronal ← Muscle

← Name ← CNS (alpha-

bungarotoxin

insensitive)

← CNS

(alpha-

bungarotoxi

n sensitive)

← Autonomi

c Gangila

← NMJ

← Subunits ← ← (alpha

7) petamere

← ←

← Agonists

(competitive)

← ACh

← Carbachol

← Nicotine

← arecoline ←

← anatoxin ← ← anatoxin

← *epibatidine ← ← epibatidine

← lobeline ← anabas

in e

← DMPP ←

← Antagonist

s (competitive)

← coronaridine ← alpha-

bungarotoxi

n

← Hexameth

onium

← Decameth

onium

← k-

bungarotosin

← Curare

← Depolarizi

ng blocker

← ← Trimethop

han

← Succinylc

holine

← Antagonist

s

(noncompetitive)

← PCP (phencyclidine)

← TEA (tetraethylammonium)

← Histrionocotoxin

← Lophotoxin

← nereistoxin← ← buprop

rion

(wellbutrin)

←

← Antagonist

(suicide)

← bromoACh

← * tree frog poison

**

Voltage and ligand gated channels and the neurotransmitters associated.

Know the agonsit and antagonist. Know the endogenous ligands. Exogenous

drugs need to know. Know which drug goes to which channel. Does it apply

to voltage gated, ligand gatied, Ia, Id, … what does the drug interact with!!!

The complicated receptors of the NMDA then the GABAa receptors and look

over the sturcutre and the modulatory sites. The NMDA subunits, NR1 and

NR2- both important. NMDA receptor in neuroplasticity. HINT HINT HINT.

Know the difference between gly and glu mediated subunits. Know the I/V

curves and what they mean for the different receptors and currents.

4/8/09 7:39 PM

← 3/10/09

← GluRs – Metabotropic glutamate receptors: mGluRs

←← L-glutamine

↓ (via glutaminase)

← L-glutamate (mitochondrial) α-ketoglutarate (mitochondrial)

dicarboxylate carrier outside of mitochondria alpha-ketoglutarate

(cytoplasmic) L-glutamate via AA (cytoplasmic) L-glutamine via

glutamine synthase (GS) or GABA via (glutamate decarboxylase aka GAD) in

inhibitory neurons because GABA is an inhibitory neurotransmitter

←← Na+- dependent: Excitatory Amino Acid Carrier-1 (EAAC-1)

← Na+- dependent: Glu Transporter-1 (GLT-1)

← Na+- dependent: Glu Aspartate Transporter (GLAST)

← H+ and Mg++ dependent Vesicular ATP-ase Glutamate Transporter

(VGlu-T)

← Na+ and G+ dependent Glutamine Transporter (Gln-T)

←← Early structural model of mGluRs

← Current structural model of mGluRs – Homodimers

← Regional expression varies: mGluR1, 5, 6 – due to experience!!

Hippocampus and cerebellum – mGluR1

← GluR5 in the amygdala

←← Gene expression and metabotropic function

← They are numbered mGluR1-8 and all homodimers

← Class I

mGluR1 and mGluR5

functionally they increase IP3 and Ca2+

Class II

mGluR2 and mGluR3

functionally decrease cAMP

← Class III

mGluR4 and mGluR6-8

functionally decrease cAMP

←

← Defining GluRs by their effectors

←← mGluR functional attributes

Involved in:

o perception of pain

o mood/affect, especially anxiety

o learning and/or memory

o blood flow / headache

Modulation of the activity of:

o Voltage-dependent ion channels

o Transmitter release

o Ca++-dependent ion channels (K+)

o Ligand-gated ion channels

←← Group I effector mechanisms

← Glu mgluR1/mGluR5 Gq PLC & PIP2 IP3 Ip3-R or DAG

PKC phosphorylation of ion channels

← Agonist (competitive)

Glu endogenous

Ibotenate

DHPG (3,5-dihydroxyphenylglycine)

← Antagonists (competitive)

CPG (carboxyphenylglycine; especially 4-CPG)

←← Group I agonist can increase excitability

There is no AHP after DHPG is added; spike-frequency

accommodation blocked and easily excited

But both pre and postsynaptic effects are observed

Ca++ hypothesis disproven

←← Group I agonist can

cause headaches

reduce transmitter release by reducing the Ca++ influx

← Group II, III effector mechanism

← Glu Group II, III Gi AC decrease cAMP decrease PKA

decrease

← Group II

agonists

o Glu

o NAAG (N-acetylaspartylglutamate)

Antagonist

o EthGlu (ethylGlu)

← Group III

Agonist

o Glu

o AP4

Antagonists

o MAP4

←← 3/12/09

← GABAbRsII

← GABA biosynthesis and metabolism

← Glu

← ↓ (GAD)

← GABA

← ↓ (GABA-T) *blocked by

GABAculine

← Succinate Semialdehyde

← ↓ (SSDH) *blocked by Valproate

← Succinate

←← Valproate strongly facilitates CNS inhibition

It facilitates the GAD enzyme and prevents the breakdown of GABA. This

increases the transfer from Glu Gaba. This causes inhibition!

←

← GABA Transporters (GAT) Pharmacology

VGAT (vesicular GABA transporter): GABA

o Nipecotate

o Vigabatrin

GAT1 (neuronal, glial): GABA

o Nipecotate

GAT2 (pia, arachnoid): GABA, Beta-alanine

o Nipecotate

GAT3 (neuronal, glial): GABA, Beta-alanine

o Nipecotate

←

← GABAergic synapse

Package gaba into vesicles ant release it onto Gaba receptors that

generate ipsps. Presynaptically there was an action potential.

GABABR are found posynaptically and presynaptically. There are

differences in their interaction tho. The gaba can be transported

back presynaptically and it can be transported into mitochondria or

broken down they can also be broken down in glial cells.

←←← Two subunits: coexpression

GABA B receptors are obligate heterodimers: one GABA b1 and one

GABAb2 subunits are needed. One binds the g-protein and one binds to

the GABA.

Gaba b1 and GABA b2 subunits exist and coexpressed in the same cells and

regions and rate.

If you only express Gaba b1 then they are stuck in the endoplasmic membrane

and doesn’t make it to the plasma bembrane. If only gabab2 are expressed then

the GABA doesn’t interact with the receptor.

←

← GABAbR-effector coupling

GABA binds to one of the two components of the dimmer and

activating the g protein on the other part of the dimmer.

The Gi/o family of proteins;

o The α subunit ↓ the AC

o The βγ subunit ↓ VDCCs (blocking depolarization) and ↑ the

activity of VDKC (decreases the resting potential).

PTX (pertussis toxin blocks the Gi/o Proteins).

←← GABA BR ligands

AGOo GABA (endogenous)

o Baclofen (exogenous antispasmatic drug)

ANTo Phaclofen

o 2-OHsaclofen

←

← Effects of divalent cations on GABA BR ligands binding Some enhance GABA binding

o Mn2+ = NI2+ >Mg2+ >Ca2+

o Physiological [Mg2+] or [Ca2+

Some inhibit GABA binding

o Hg 2+ > Pb2+

Phosophorylation of GABABRs enhances βγ coupling to GIRKs; enhanced

dissociation of βγ from Rs. The phosphorylation of the dimmer causes the G

protein to dissociate.

←← GABABR block of VDCC via Go βγ subunits

Antibody for βγ -Go will block the affect of baclofen

←

← Presynaptic GABABR decrease postsynaptic GABA IPSPs GABA will inhibits it’s own release with autoreceptor effect. If you block the

presynaptic GABABR Gi paired pulse suppression/depression.

←

← GABABR activates slow IPSC Slow outward K+ current: GIRK (more than ½ seconds) found postsynaptically in

neurons

3/24/09

Cholinergic receptors mAChRs

Diffuse central cholinergic systems – GABA is released from these systems

after activation from the

LTN = laterodorsal tegmental n.

NDB = n. diagonal band

MS = medical septum

H = Habenula

NBM – N Basilis of Meynert

ACh is involved blood pressure regulation and

Biosynthesis: ChAT (choline acetyl transferase) positive cholinergic neurons

Degradation: Multiple isoforms of AChE (Aceylcholinesterase) **it is not taken

up by glial cells or reuptaken. It is degraded in the synapse.

ACh biosynthesis and metabolism

Acetyl CoA and Choline are the substrates and ChAT is the enzyme which

catalyzes the ACh and CoA (products). ACh in the synapse is broken down

by AChE into Acetate and Choline

AChE ligands I: OrganophosphatesAChE ligands I: Organophosphates – the ACh is left inside the synapse and

the AChE isn’t able to do its job.

Ligand Duration Use (dose dependant)

Long Irreversible Insecticide WMD

Sarin [GB] X X

DDT X X

Diazinon X X

Malathion X X

AChE Ligands II: Clinical AChE drugs

Inhibitor Duration

Short Long

Donepezil (Aricept) X

Physostigmine X

Regenerator of AChE

activity

Duration

Short Long

Obidoxime X

Vesicular ACh transporter (VAChT) – proton dependant (requires 2 protons per

molecule of ACh. Protons must be pumped in via an ATPase from the cytoplasm into the

vesicle along with ATP via an ATP transporter.

5 Classes of mAChRs

Name M1 M2 M3 M4 M5

Effectors Gq Gi Gq Gi Gq

Evens

- ↓ AC

- Modulate IM

Odds

- ↑ PLC

Uses/abuses of mAChR ligands

- Clinicalo reduce secretions (atropine)

o prevent motion sickness (scopolamine)

o treat Alzheimer’s (Donepezil)

o treat autonomic disorders (M3 ANT)

o dilate pupils for ophthalmic exams (M3 ANT)

o treat severe diarrhea (M3 ANT)

o slow heart rate (M2 AGO)

o treat mushroom/anti-AChE poisoning (atropine)

- Non-clinicalo dilate pupils for beauty (atropine)

*Newly discovered –allosteric modulation

- Brucine: enhance muscarinic agonist binding

mAChR Agonists

LIGAND Receptors

M1 M2 M3 M4 M5

Acetylcholine

(ACh)

X X X X X

Carbachol X X X X X

Muscarine X X X X X

Oxotremorine X X X X X

Pilocarpin E X

mAChR Antagonists

LIGAND Receptors

M1 M2 M3 M4 M5

Atropine E X X X X X

Scopolamine X X X X X

Pirenzepine X

Gallamine X

4-DAMP X

Tropicamide X

Smooth muscle contraction via m3 mAChRs via IP3R mediated

Ca2+ nM muscarine

Extremely slow IPSPs via m2AChRs

Onset 30-90 s after mAChR ligand binding; amplitude 2-3 x normal AHP;

GIRKs: Gi βϒ subunits

After-depolarization; Ca2+ spikes (m1,3 mAChRs)

Activating T-Type Ca2+ channels

Slow depolarization: Gq βϒ subunits

Block of HVA VDCCs by M1, 3 Rs

Mediated by Gq α subunits

Im block by muscarinic agonists

Gq α subunits

Block of sAHP by m1, 5 AChRs

Anti-AChEs raise synaptic ACh concentration

Anti – AchEs block “normal” slow AHPs via mAChRs (metrifonate

Effects of chronic anti AChE treatments linger in vitro

3/26/09

Central DA minergic pathways

MFB – medial forbrain bundle (path from the NS and VTA to the rest of brain)

SN substantia nigra – basal ganglia

VTA = ventral tegmental area – the rest of the brain

Catecholamine biosynthesis

Tyr (tyrosine crosses BBB) TH (tyrosine hydroxylase) DOPA AAAKC

(alpha amino acid decarboxylase) or DOPA decarboxylase (DDC)

Dopamine (in the VTA and SN this is the end) but others continue using

dopamine Beta hydroxylase norepinephrine (adonergic) in adrenal

cortex it is converted into Epi (epinephrine) via PNMT

TH: The rate limiting enzyme

- it has several amino acids that can be phosphorylated. Cam-KII, PKA, PKC, ERK, and cdc-

like-K. PHosphorylating increases activity and phosphotases decrease activity.

LDOPA when used to treat Parkinson’s it is used with Carbidopa (blocks TH)

so that tyr isn’t converted. Carbidopa doesn’t cross BBB. LDOPA is

transported into the brain slowly.

Transmitters vs false transmitters

L-DOPA is converted into DA via AAADC. False neurotransmitter (alpha-

methyl-DA) is created by the same enzyme. DbetaH converts it into alpha

methyl NE

DA degradation

DA

can be converted into 3-methoxy-tyramine via COMT. MAO converts 3-

methoxy-tyramine into HVA (homovanillate). DA can also be converted into

DOPAC via MAO + aldehyde deOH. COMT converts DOPAC into HVA.

Uses and abuses of DAminergic ligands

- appetite suppression

- antidepressants

- antipsychotics (including treatment of schizophrenia)

- fatigue suppression

- enhance attention

- treating motor dysfunctions (parkinsons)

- pressor effects

Recreational

- fatigue suppression

- enhanced attention

- mania mimicry

- mild hallucinogenic effects

Biogenic amine hypotheses of affect/psychosis

As you age your biogenic amine are reduced… may lead to depression. All

three seratonin, dopamine, norepinephrine are involved in mood, emotion.

And cognitive function

VTA frontal ctx – hypo (negative symptoms)

VTA Nucleus accumbens – hyper (positive symptoms)

Transporters; vesicular DAT (VDAT)

12 transmembrane segments and proton-dependent transport. Only

requires one proton (ATPase) and the ATP site is outside the vesicle so no

ATP import is required.

Vesicular Transport inhibitors (block filling of all biogenic amines)

- Reserpine – most widely used

Synaptic DAT (DA back into the cell)

12 transmembrane protein. Na/CL-dependent transport; Oubain indirectly

inhibits it, by blocking Na+/K+-ATPases.

Reuptake inhibitors

DAT

(DA transports)

NET

(NE transporter)

SERT

(5-HT transporter

Indatraline* (antidepressant)

cocaine

Bupropion (wellbutrin)*

Nomifensine (merital)

Duloxetine (cymbalta)

Amphetamine

Reboxetine*

Atomoxetine**

Imipramine*

Amitriptyline*

Venlafaxine*

Clomipramine***

*antidepressants

** ADHD

*** anxiolytics

Amphetamine and analogs

Amphetamine, detroamphetamine, methamphetamine

Analogs – methylphenidate (Ritalin), cocaine, phenmetrazine, MDMA

ADD works to block the reuptake of DA in the prefrontal ctx (inhibiting

forbrain).

Amphetamines increase synaptic DA

Block reuptake in 2 ways

1. compete for DAT

2. upregulate MAP-K phosphorylate DAT internalize DAT

DA-specific neurotoxins

MPTP glial MAO-B MPP+ (shuts down kreb cycle in mitochondria)

6-OH-DA

1. Both MPP and 6OH DA are substrates for DAT

2. Both are then taken into mitochondria

3. Both block oxidative metabolism

4. Both kill DA neurons selectively and dose-dependently

5. Both produce behavioral effects mimicking parkinsonism

DARs are diverse

7 transmembrane segments; mono-, di-, and heterodi-meric (s. SST

(somatostatin), etc)

DAR types

Name D1 D2 D3 D4 D5

Synaptic

location

Post- Pre- and

Post-

Post- Post- Post-

Alpha

subunit

effector

Gs Gi Gs

Beta

gamma

subunits

effects

Decrease

VDCC,

VDKC,

CDKC

The ctx has D1-D5

Hypothalamus has D3 + D5

Corpus striatum has D1 + D2

DA agonists

LigandDA receptor type

Other catecholamine

receptors

D1 D2 D3 D4 D5 Alpha beta

Dopamine X X X X X X

Apomorphine X X X X X

Dihydrexidine XX X

bromocriptin

e

X X X

Praminpexole X XX

Ropinirole X XX

DAR antagonists

Ligand DA receptor type

D1 D2 D3 D4 D5

Spiperone XXX XXX XX XX XX

Ecopipam X

Amisulpride XXX X

Chlorpromazine* XX X X

Trifluoperazine* XX X X

Haloperidol* XX X X

Resperidone* XX X X

out patient drugs

Neuroleptics vs. tricyclic antidepressants vs. Li+

Tardive dyskinesia – intermittent inability to move. The receptors increases

and then they can’t create more. They are taken off neuroleptic drugs they

return to the drugs after symptoms of origional problem comes back.

3/31/09

Catecholamines – Norepinephrine (NE)

Adreneric projections in the CNS

LC = Locus coeruleus - cerebellum

A1-A9 = reticular adrenergic nuclei – regulatory on the hypothalamus

Methods to alter transmission**- Alter synthesis

o facilitate, block, false transmitters

- Block vesicular storage

- Block release == Ca2+ blockers, etc.

- Direct receptor effects

o agonists, antagonists, suicide antagonists

- Block reuptake

- Block degradation

Uses/abuses of NE ligands

- Clinicalo Cardiac regulation (rhythm, rate, volume)

o Antihypertensive

o Bronchial dilation (asthma relief)

o Anti-depressant

o Anti-ADHD/ADD

o Anti-OCD

o Decongestant

- Recreationalo Hallucinogenic

o Amphetamine-like effects

Release blockers indirectly effect VNETs (vesicular norepinephrine transporters)

- block Mg2+-ATPase proton pumps specific to NE neurons

- do not cross BBB; anti-hypertensive (guan-), block arrhythmias

(bretylim)

- Sympathetic

- It is proton dependant

Antidepressants, ADHD, anziolytics, etc (SEE ABOVE CHART)

DAT

(DA transports)

NET

(NE transporter)

SERT

(5-HT transporter

Degradation inhibitors (-Is)

Enzyme MAO-I COMT-I

A-specific

(NE, 5-HT)

A- or B-

(nonspecific)

B- specific

(DA, HA)

Inhibitor Reversible Irreversible

Befloxaton

e

Harmaline Iproniazid Deprenyl tocapone

MAO-Is are still prescribed as antidepressants; deprenyl in phase III for

Alzheimer’s

Classes of adrenoceptors (NE, EPI)

- alpha

o α1: smooth muscle contraction - Gq

o α2: smooth muscle contraction – Gi (inhibiting neurotransmitter

release)

- beta: cardiac muscle contraction - Gs

Alpha 1 ( α 1) Adrenoceptors

Nameα 1A α 1B

α 1D

Expressed in:

(don’t need to know)

CNS, heart, liver,

urogential smooth

muscle

Resistance vessels,

kidney, spleen

CNS, aorta, lung,

bladder

Non-selective AGO DA

NE

EPI

Phenylephrine

Ephedrine, Pseudoephedrine

Selective AGO Tetrahydrozoline

Selective ANT

(don’t need to know)

Niguldipine

5-methylurapadil

Cycloazosin

Spiperone

Non-selective ANT Phentolamine

Prazosin

Suicide ANT Phenoxybenzamine

G-protein Gq - ↑ IP3/DAG

Decongestants, eye drops (α 1 AGO)

Ephedrine

Pseudoephedrine

Phenylephrine (nyquil)

Tetrahydrozoline (eyedrops)

Alpha 2 ( α 2) Adrenoceptors

Name α2A α2B α2C

Expressed in: CNS, Lung, vascular

muscle

Thalamus, liver,

vascular, spleen

CNS, lung

Function Autoreceptor;

Vasoconstriction,

sedation, analgesia,

anesthesia

Vasoconstriction Undeterimined

Non-selective AGO NE

EPI

Clonidine

Selective partial

AGO

LSD-25

Nonselective ANT Phentolamine

Prazosin

Yohimbine

α -subunit Gi

β-ϒ subunits Inhibit VDCCs, activate CDKCs

Antihypertensive vasodilators (alpha ANT)

Phenylethylamine hallucinogen relatives of NE- LSD

- cathine

- ephedrine

- yohimbine

- mescaline

- elimicin

Beta (β) Adrenoceptors

Name β 1 β 2 β3

Expressed in: Neuronal cardiac,

kidney

Neuronal, cardiac,

bronchial

Neuronal, cardiac,

adipose

Non-Selective AGO NE

EPI

Isoproterenol

Ephedrine

Selective AGO Xamoterol Albuterol

Salmeterol

Selective ANT Atenolol Butozamine

Non-Selective ANT Propranolol

G-protein Gs - ↑ cAMP

Sympathetic effects on cardiovascular system

- Increases VDCC (HVA) and increases VDKC (IK) and increases VDCC

(LVA) resulting in each heart beat is going be faster and stronger. Bigger

volume of blood pumped harder each time. (acute effects)

- The higher blood pressure sustained causes issues also.

Antihypertensives (β1 ANT)Atenolol – used to lower blood pressure.

**notice the suffix -olol

Brochodilators (β2 AGO)Albuterol

Salmeterol

**notice the suffix –terol

4/2/09

Indolaminergic transmitters – Serotonin (5-HT)

Peripheral 5HT

- first purified from blood plasma (serotonin): 1948 and first purified

from the brain in 1957

- total quantity of the body < 10 mg (5% of that in brain)

- Intestines 0 enterochromaffin cells enhance motility of 5HT4

- Blood vessels – platelets; vasoconstriction: 5HT1D

- Also a mitogen: enhances cell proliferation in muscle, liver but not in

the bone

5HT pathways: Raphe n. which are widely distributed from the pons down

the brainstem and project throughout the rest of the brain. The largest are

the dorsal and median Raphe n. They are pyramidal neurons and they have

afterhyperpolarization (modulated by apamine). These neurons are

important in the sleep/wake cycle. They are almost completely silent when

sleeping and active during waking.

Hertogeneous 5HT fiber systems

- Doral Raphe n. has diffuse projections

- Median Raphe n. has specific projections

Serotonin (5HT) synthesis and metabolism

Compound Enzyme Inhibitors

L-tryptophan

↓

Tryptophan

hydroxylase

(TrpH)

Fenfluramine

L-tryptamine (Tra)

↓

α aromatic amino

acid decarboxylase

(DDC or AAADC)

Carbidopa

5hydroxytryptamine (5HT)

↓Monoamine oxidase

(MAO-A)

MAO-A inhibitors

5-hydroxyindoleacetaldehyde

↓Aldehyde

dehydrogenase (AD)

5-hydroxyindoleacetate (5-HIAA)

MAO-A doesn’t have A’s in abr. (NE, 5HT)

MAO-B has the A’s (DA, HA)

SERTs - ATPase pumps protons into the vesicle

- SERTs pump 5HT and Na+ & Cl- into the vesicle and 5HT and K+ outside the vesicle

SSRIs (antidepressants and anti OCD)

DAT NET SERT

Indatraline

cocaine

Bupropion (wellbutrin)

Venlafazine (Effexor)

Clomipramine (anafranil)

See other chart See other chart Fluoxetine (frozac)

Sertraline (Zoloft)

Citalopram (Celeza)

Paroxetine (Paxil)

Fluvoxamine (Luvox)

5HT1Rs

5-HT1A 5-HT1B 5-HT1D 5-HT1e 5-HT1f

Tissue Neuronal; smooth

muscle

Rodent neuronal

autoreceptor;

smooth muscle

constriction

Human

neuronal

autoreceptor;

smooth

muscle

constriction

Widely

distributed

Ubiquitous

agonist

5-HT

quipazine

Selective

full

agonists

Buspirone

DMT

(dimetheyltryptamine)

Ergotamine (mold)

sumatriptan

Selective

antagonist

s

Spiperone isamoltane

Antagonist pindolol

G-Protein G i/o

Anziolytic (5HT1a agonist) – buspirone

Migraine therapy (5HT1b/1d agonists)

- Ergotamine – hallucinogen

- sumatriptan

**cause vasoconstriction – stabilization of either state… can feel dull; but

reduces migraines

5-HT2Rs

5-HT2A 5-HT2B 5-HT2C

Nonselectiv

e agonists

5HT

Quipazine

Partial

agonists

LSD-25

Psilocybin/psilocin

Pyschedelic

phenylethylamines

LSD-25

Psilocybin/psilocin

Pyschedelic

phenylethylamines

Selective

agonists

DMT

DOM (STP)

agomelatine

Selective

antagonists

Ketanserin Metergoline ritanserin

Nonselectiv

e antagonist

Mesulergine

dibenzyline

G-Protein Gq

Psychedelic effects mediated by 5HT2ARs

- competitive antagonists do not block psychedelic effects

Indolaminergic psychedelics (50HT2a agonists)

- DMT

- Psilocybin

- LSD-25

Hallucinogens bind promiscuously

- alpha 2 receptors – assess using tritrated alpha 1 and alpha 2

antagonists

- 5ht receptors assessed using titrated 5ht1 and 5ht2 antagonis

- D2 receptors assessed using tritiated D1 and D2 antagonist

- LSD receptors assessed using titrated LSD

Clinical use of 5-HT2 ligands

- anti-schizophrenic (5HT2a antagonists)

- satiety stimulants (5HT2c agonists)

5HT3Rs

5HT3Rs

Nonselective agonists 5HT

Quipazine

Selective agonists CBG

Selective antagonists Ondansetron (keeps you from

vomiting)

Zacopride

Mechansism Petameric cation channel (weak

selectivity for Na+)

Antiemetics (5HT3 antagonists) – used extensively to alleviate nausea in

chemotherapy

- ondansetron

- zacopride

- also used in IBS treatment

Nootropics (5HT3 antagonists) – the problems is they don’t cross the BBB

and would cost $100/dose/day to take enough drugs to cause the nootropic

effects.

5HT4-like receptros

5HT4 5HT6 5HT7

Nonselective

agonists

5HT quipazine

Selective AGO EMDT COAT

Selective ANT amoxipine

Nonselective

antagonists

clozapine

G-protein Gs

5HT5Rs

5-ht5a 5ht5b

Nonselective

agonists

5HT

LSD

Melatonin

Serotonin 5HTNacetylase Nacetyl-5HT 5-OH-indole-OMT melotonin

(pineal gland) *just know that it is serotonin synthesizes melatonin in pineal

5HT specific neurotoxin

- PCPA: highly specific for 5HT neurons similar in mechanism to MPP+

REVIEW PERIOD

Synthesis and metabolism of the neurotransmitters

mGluR

Get the information off the website

- Three classes

o Class 1: mglu r1 mGluR5

o Class II: mGluR2 m GluR3

o Class II: mGlu

o Class I increase IP3 and Ca+

o Class II and III decrease cAMP

o Involved in perception of pain, affect and mood, learning and

memory, modulating activity of voltage dependent ion channels,

modulating

Glutamate metabolism (website information)

L-glutamine glutaminase lGlutamate (mitochondrial) alpha …

Don’t need to know the cofactors/substrates or inhibitors

** maybe aminooxyacetic acid as an inhibitor because it’s useful at different

sites

GABA Transporter Blockers: Nipecotate blocks all VGAT, GAT1, GAT2, GAT3

Vigabatrin blocks VGAT

ACHC

Dopamine

- reuptake inhibitors (prescribed as antidepressants)

o buproprion

o nomifensine

o indatreline

o mazindol

o amphetamine

- amphetamines and analogs

o amphetamines

o dextroamphetamine

o methamphetamine

o methylphendate

o Cocaine

o Phenmetrazine

- DA specific neurotoxins

o MPTP

o 6-OH-DA

Norepinephrine

- major source of NE in the brain – locus coeruleus

- peripheral release blockers

o quanathedine, guanadrel, bretylium

o CNS Ganglionic synapse NMJ

o Sympathetic NS

- Cental release blockers (cross BBB)

o Guanathedine, bretylium

- NE classes of receptors

o Alpha 1 accitvates Gq which increases PLC

o Alpha 2 – gi decresase cAMP

o Beta1 and beta 2 Gs increase cAMP

- phynylethylamine hallucinogenic relative

o cathrine, ephedrine, amphetamine, yohimbine, LSD-25,

Mescaline, MMDA

- NET blockers

o Atomexetine

o Desipramine

o Nortriptyline

o Amitryptyline

o Indatrelin

- Degradation Inhibitors

o MAO-A specific (NE, 5HT)

Specific receptors and antagonists – Know the non-specific

Serotonin – synthesis and metabolism

- produced in the bidbrain and the pontine nuclei, major source : raphe

nuclei

- SERTs

o VSERTs- H dependent (ATPAse)

o SERT (blocked b SSRIs) = Na and Cl dependent

o Both block by fenfluramine

- 5HT1 – Gi

- 5HT2 – Gq

SSRIs

Antidepressants

Seratonin Hallucinogens

- DMT

- Psilboc

←← 4/7/09

← HistamineHistamine (last of the biogenic amines)←← Peripheral HA

← - Inflamation (in mast cells): H1Rs orgasm

allergy

congestion

← - Digestion: H2Rs gastrin

Parietal cells create gastric acid

← - Immune Response: H4Rs basophils

neutrophils

bone marrow

←

←← HAminergic neurons: transport, synthesis, degradationHAminergic neurons: transport, synthesis, degradation

L-amino acid transporter takes HA into the cell (AAAT)

Histidine is converted by histidine decarboxylase (HD) into histamine and

transported into vesicles via Vesicular MonoAmine Transporter (VMAT).

Histamine methyltransferase (HAMT) breaks down histamine into

telemethylhistamine

←

← CNS HA : Hypothalamic tuberomamillary nuclei* (TMN) project to the

rest of the body.← *(right above the mamilary bodies)

←← Tuberomamillary neurons (TMN

← - large soma, dendrites

← - long thin poorly myelinated punctate axons (slow, large number of

synapes

← - adjacent to VLH hypocretin (hypothalamus cretine neurons)

HA: Role in waking and sleep. The firing rate is high when you are awake and drops during SWS and almost turns

off during REM.

Antihistamines make you lethargic

Modafinil – increases HA release, increases alertness

HAR Types

Receptor H1H1 H2H2 H3H3 H4H4

g-protein Gq Gs Gi Gi

Neuronal

location

Postsynaptic Postsynaptic Presynaptic postsynaptic -

Global

Function

Waking state;

arousal; appetite

suppression

Waking state;

arousal

learning and

memory

Autoreceptor;

regulate

transmission;

inhibit -waking

arousal

? -

Other

Tissues

Mast cells Parietal cells Basophils;

neurophils;

bone

marrow;

smooth

muscle

Peripheral

Function

Inflammation;

congestion;

orgasm

Acid release allergies

H3 is the only autoreceptor. - If you block the receptor you increase firing rate of the postsynaptic neuron.

- H3 presynaptic block of Voltage Dependent Ca Channels.

- An AGO will decrease the inward current through VDCCs.

- Autoreceptors act like this

Uses/potentials of HA ligands

- Peripheralo Allergy treatments (peripheral H1 ANT)

o Anti-congestive (peripheral H1 ANT)

o Anti-inflammatory (peripheral H1 ANT)

o Antacids (peripheral H2 ANT) *not really antiacids but go the problem of the

acid.

- Centralo Anti-emetics/anti-vertigo (H1 ANT)

o Hibernation, sleep (H1 ANT)

o Stimulants (H3 ANT)

o Alzheimer’s therapies (H3 ANT)

o Nootropics (H3 ANT)

o ADD therapies (H3 ANT)

o Anti-obesity treatments (H3 ANT)

HA Agonists

Competitive

AgonistHAR

H1H1 H2H2 H3H3 H4H4

Histamine (HA) X X X XDimaprit XProxyfan (partial) XImetit X X

Classic antihistamines: Competitive ANT

Competitive ANT HARH1 H2 H3 H4

Cetirizine (zyrtec) XClorpheniramine *** XDimenhydrinate (Dramamine) XDiphenhydramine (Benadryl) XDoxylamine (Unisom) XFexofenadine (Allegra) XLoratadine (Claritin) XMeclizine (Antivert) XPromethazine (phenergan) Xallergy meds

anti vestibular

Sleeping pills

Other HAR antagonistsOther HAR antagonists, inverse agonists

Competitive ANT HARH1 H2 H3 H4

Cimetidine (tagamet) XClobenpropit XInverse AGO ***Increases Neurotransmitter Release… similar to the

antagonist.

Thioperamide X

H2 agonists increase CA1 excitability

- If the H2 agonists is administered there is no afterhyperpolarization

H3 antagonists: nootropic and dietary benefits…. Every learning task the H3

has shown to enhance.

Exam… know the receptors, antagonist, non-competitive. Know the

mechanism of action. Know the clinical uses… digestion, asthma, and heart

rate information. Know the biosynthesis and the degradation of the

neurotransmitters and their enzyme and rate limiting…. Know the transports-

vesicular and cell membrane transporters. Know the drugs that blocks NETS

SERTS ECT.

4/8/09 7:39 PM

← 4/14/09

← Transcription factors etc.

← Steroid Hormones

←← Ganadal steroids and neural plasticity. –

← HRT hypotheses: for heart disease prevention: disproven;

← for osteoporosis (bone loss), “hot-flash” prevention: supported;

*possible breast cancer increase due to hormonal treatment

← for cognitive support (esp. in Alzheimer’s): uncertain *women have

higher rates of Alzheimers after menopause

←← Gonadal steroid biosynthesis

← - Cholesterol

← ↓

← - Progesterone

← ↓

← - Testosterone (testes in males, ovaries in females)

← ↓

← - Estradiol

←← Biosynthesis

← Testosterone →estradiol (E2) ⇔estrone (E1)

← ↓ (alpha-reductase) ↓

← DHT estriol (E3)

←← Hormonal regulation of estrus

← P. Pitutiary

← ↓ (GnRH) *gonadotropal releasing hormones

← Anterior Pituitary

← ↓ (FSH & LH) – the same time there is an increase in temp.

← Ovaries

← ↓ (Progesterone and Estradiol)

←← zGonadotropin hormone Rs (metabotropic and cytokine)

←

7- tansmembrane segments cytokine

receptors and homodimer- singl transmembrane segment

← Hormon

e

← GnRH ← FSH ← LH ← Prolacti

n

← Release

d by

← Posterior

pituitary

← Anterior

pituitary

← Anterior

pituitary

← Anterior

pituitary

← Recepto

rs expressed in

← Anterior

pituitary

← Egg

follicle

← Egg follicle,

testes

← Mammar

y glands

← Stimulat

es

← Producti

on of FSH, LH

← Maturati

on

← Corpus

luteum/spermatogenesis

← lactation

← Signalin

g

← Gq ← Gs← ← JAK/STAT

pathway

← JAK - Janus kinase

← STAT- Signal transduction and activator of transcription

Steroid receptors: - Intracellular, not membrane bound

- Hormones have receptors in the cytoplasm and then its translocated into the steroid

receptor complex to the nucleus. Binding of complex to DNA regulatory site.

Transcription then translation

1. Ligand binding

1.5 HSP (heat-shock protein) release

2. Translocation via nuclear pore complex

3. Dimerization and DNA binding

4. Gene transcription

5. Also includes RNA transport, insertion in ER, translocation into protein, and possible

post-translation protein modification.

Steroid Hormone Receptors

Receptor Gonadal Steroids Adrenal Steroids

Estrogen Androgen Progesterone Glucocorticoid Mineralocorticor

d

Endogenous

Agonists

Estradiol

Estriol

Estrone

Testosterone

DHT

Progesterone Cortisol

Corticosterone

aldosterone

Antagonists Tamoxifen Flutamide Mifepristone Spironolactone

Agonist

Effects

Regulate

hormone

secretion

Regulate

cholesterol

metabolism

Increase lipid

protein

synthesis

Breast tissue

stimulation

Maintain

neural

plasticity

Maintenance

of sex drive

Enhance bone

Ca2+ retention

Increase lipid

protein

synthesis

Maintain

neural

plasticity

Enhance bone

Ca2+ retention

Stabilize uterine

proliferation

Stabilize lipid

metabolism

Increase hepatic

gluconeogenesis

Increase protein

catabolism,

glycogenolysis

Increase BP

Increase HR

Immunosuppression

Na+ retention

/K_excretion by

kidney distal tubules

ERs: Estrogen receptors

Dimeric receptors: ERα ERβ

Most are heterodimers, widely distributed throughout, including the CNS

Agonists: Birth Control Pills/HRT

Formulation Generic Brand name

Estrogen only Estradiol Premarin

Combination monophasic Ethinyl estradiol Desogen

Progestin only Norethindrone Microanaar

Anti-estrogens

ER-antagonists – used in treatment of breast cancers to block proliferation of

estrogen-sensitive tumor cells

Tamoxifen

Clomiphene

Or aromatase inhibitor – anastrozole

Anti-progestins

Progesterone Rs antagonists are used as arbortifactants to disrupt

maintenance of uterine endometrial lining to block fertilized egg

implantation. Mifespristone (RU486) morning after pill prevents egg

implantation

Metabolites of Androgens

Active Inactive

DHT (another one too) Don’t need to know

Testosterone

Developmental regulation of testosterone

Plasma testosterone in the trimester during neonatal and then decreases

and then increases during first year of life. It goes way down and then

during puberty it increases until late adulthood.

Cellular effects of androgens

Pituitary (LH) Testes (testosterone) target cells

Target cells

- AR-A

o GsRH regulation

o Bone and muscle growth and anabolic effects

- AR-B

o Sermatogenisis

o Sexual differation and virgor

Anabolic steroids: androgens

o Exogenous anabolic steroids can increase skeletal (bone) and skeletal muscle

mass.

o They also increase blood pressure and cardiac muscle mass, which can lead to

rhythm disturbances and sudden cardiac arrest

o Excess anabolic steroid use may increase aggression, rage, linked to arrest for

violent, disruptive, or sexually violent behavior

o Anabolic steroids cause scalp hair loss

o Finally, anabolic steroids can trigger prostate and brain cancers

- testosterone

- DHT

- Oxandrolone

- Oxymetholone

Anti- Androgens

- competitive ANT

o flutamide

- alpha-recutase inhibitor

o finasteride

used for: treatment of sex offenders, prostate cancer, male-pattern baldness (vs minoxidil

rogaine K-ATPactivator)

Biosynthesis of adrenal steroids

Cholesterol progesterone cortisol

↓

corticosterone (smaller amt) aldosterone

Steroid synthesis inhibitors

Inhibitor Mechanism Macroscopic effects

aminoglutethimide

trilostane

ketocon

H-HPA axis and stress hormone regulation

Hippocampus (CA2 and CA3 pyramidal cells) release glu hypothalamus (paraventricular

N) posterior pituitary (neural lobe) release CRF onto the anterior pitutaty

(corticotropes) ACTH is released onto the adrenal cortex (fasiculata cells) releasing

corticosteroids which circulate causing the following:

- GREs (glucocorticoid response elements )

- Immunse suppression

- Increase HR

- Increase BP

- Increase catabolism

- OR feedback onto the hippocampus to shut the cycle down

Dual cleavage of POMC to yield ACTH

- two peptidases are cleaved via endopeptidase and caroxypeptidase

Adrenal (endogenous) steroids

Gona glomerulosa – aldosterone

Zona glaciculata – ACTH and cortisol

adrenal steroid secretion rates

Type Steroid Rate/day

Corticosteroid Cortisol 10-20 mg

Corticosterone 2-4

Clinical (exogenous) corticosteroids

- betamethasone

- dexamethasone

- hydrocortisone (synthetic cortisol)

- prednisone

Plasma protein binding affects corticosteroids

- over 9/10ths get to the target… the rest is bound to the plasma binding protein.

Major clinical corticosteroid uses

Corticosteroids and mineralocorticoid Rs

Cortisone Cortisol Aldosterone

↓X ↓binds ↓binds

mineralocorticoid receptor

4/21/09

CNS depressants: EtOH and other anesthetics

DOSE: for governemtn purposes, 1 “serving” of ethanol ~1ox. Of 80proof (40% EtOH by vol.)

Structure of common alcohols

Products of carbohydrate fermentation. We can only take in ethanol.

Differential distribution and clearance of EtOH

When taking in ethanol oralsly it goes through the gus portal vein vena cava, arteries,

peripheral veins

EtOH degradation in CNS

EtOH is broken down by alcohol dehydrogenase (AD) and NAD and H+ NADH

Acetaldehyde is carried into the mitochondria and aldehyde dehydrogenase (ALD) turns it

into acetic acid. Acetic acid turns into H20 and CO2

EtOH can alter DA metabolism, producing “opioids”

DA will take an alternative pathway and condencse into tetrahydropapaveroline (HTP). THP

will create opioids. This is due to aldehyde dehydrogenase (normally used in DA

degredation) being used to degrade EtOH

Acute effects of EtOH

- Initial , low dose (1-2 oz. EtOH/75kg)

o Stimulatnt; social lubricant” due to lowering of cognitive inhibitions; slight

motor impairment

- Laster, high does (>4 ox EtOH/75 kg)

o Depressant; obliteration of cognitive inhibitionas; servere cognitive and motor

impairments; aggression; emetic reflex; sedation

- Next day (after high dose)

o Hangover: mixture of sympathetic a tivation and dysfunction (nincreased BP,

dry mouth, etc)

Headache, irritiability common after

Chronic Effects of EtOH

Effect Probable mechanism

Sedation

Increased seizure threshold

Anterograde amnesia

BDP independent enhancement of GABA-Ar

function

Euphoria

Memory impairment

Analgesia

Sedation

Delta

Alcoholism

- tolerance tends to develop rapidly

- dependence tends to develop more slowly

- well defined genetics links (dependence prone)

- gradual development of reverse tolerance (impaired metabolism)(

- multiple motor effects, some of which habituate

- Korsakoffs, other vitamin deficiency effects

- Social issues, socieoeconomic outcasting

- Societal role in definitions of “problem dringking, binge drinking partying

- Recidivism high, long-term prognosis poor

Rating depth of anesthesia

Volatile (taken in through the lungs) Anesthetics

Nitrous oxide

Diethyl ether

Chloroform – liver toxicity

Isoflurane – commonly used

Sevolurane –

Instead of giving an injection (which goes to the liver via metabolism) it goes through the

lungs then other systems then the liver.

Old “membrane fluidity” theories – they thought the channels changed shape of all the

proteins

Tandem-pore K+ channels

Name Tamdem poore

Ca 2 sensitivity Insensitive

Ligand seneitivie ?

Activation -60mV/-40mV

Inactiavition Slow (s)

Actiavatiors Isoflurane

Sevoflurane

Blockers Unknown

Hyperbaric Oxygen as an anesthetic, toxin

Dissociative anesthetics – feeling of being detached from the physical self

- ketamine

- phencyclidine (PCP)

- dextromethorphan

Sigma Opiate effects

Name Sigma

Classical 1 2

Ligands Haloperidol

Detamine

PCP

Pentazocine

Haloperidol Haloperidol

Mechanism Unknown Unknown unknown

Neuroleptics (used to treat schizophrenia) Underlined D2 blocker

Weighing the risks, benefits of anesthesia

- benefits

o allows complex, painful surgical technique performance

o allows development of procedures (eg killing the patient during heart surgery)

that would otherwise be impossible

o gives surgeons time to be careful in procedures

- Risks

o Some patients fail to recovers

o Constant monitoring required, particularly to avai anoxia \\

o Illicit use of anesthetics increases life-threatening risks

- Balance

o Valuable ligands, absolutely required by modern medicine

o Life-threatining nature of these ligns requreiesnd

4/23/09

NSAIDs, peptides and alkaloids – opiates, opioids, and other analgesics

Next Thursday is the review for the final exam.

Analgesics (“pain-killers”)

- Analgesia = relief of pain

o Surgical

o Acute

o Chronic

o Phantom

- Analgesic formulations

o Short-acting

o Intermediate

o Long-acting

1897 Bayer Ad

NSAIDs (non-steroidal anti-inflammatory drugs)

Cyclooxygenase inhibitors (COX-inhibitors)

- salicylates:

o Aspirin (bayer) **aids in platelet breakup

- Traditional NSAIDs:

o Acetaminophen (Tylenol)

o Ibuprofen (Advil)

o Naproxen (Alleve)

COX-1 – required for normal gastric function

COX-2 – active in inflammatory actions, cardiac/cardiovascular function

- Celebrex (celecoxib) *joint pain, arthritis

Uses/abuses of opiate peptides

Clinical uses

- analgesia

- cough suppressant

- sedation

- prevention of withdrawal

Recreational uses

- analgesia

- Sedation

- Prevention of withdrawal

- Other psychotropic effects

Conserved sequences among cloned opiate Rs.

Receptor

Name

μ Δ Κ Nociceptin

Protein MOP1 MOP2 DOP1 DOP2 KOP1 KOP2 KOP3 NOP

End.

AGO

Endophins Enkephalins

Deltorphins

Dynophins Nociceptin

AGO

affects

Analgesia

Euphoria

Intestinal inhibition

Respiratory-depression

Analgesia

Intestinal inhibition

Analgesia

Dysphoria (unpleasant)

Supraspinal pain

Spinal/peripheral

analgesia

ANT

(specific)

Cyprodime Naltriben

ANT Naloxone

Naltrexone

Diprenophine

G protein Gi/Go

Stucture of endogenous ligands

POMC (proopiomelanocortinin) – precursor to the opiates

Exogenous “organic” opium alkaloids – from poppies

- Morphine

- Codeine

- Narcotine

- Papaverine

- Thebaine

Modified opiates- diacetylmorphine (heroin)

- hydromorphone (dilaudid)

- oxycodone (percodan, oxycontin)

- hydrocodone (vicodin)

Synthetic Opiates (piperidine analgesics)

- Buprenophrine (Buprenex); partial AGO, high affinity, long Kd

- Methadone (Dolophine)

- Propoxyphen (Darvon)

- Meperidine (Demerol)

- Fentanyl – regulated because

Opiate antagonists – **OD treatments**

- naloxone

- naltrexone

- diprenorphine

Side effects: instantaneous onset of severe withdrawal

Addiction/dependence- Physical

o Development of tolerance

o Other kinases upregulated to compensate for PKA suppression

o Rate of development differs by cellular phenotype

- Psychological

o Need for hedonic effects (which decline)

o Need to avoid withdrawal symptoms (increases)

o Sedation soothes anxieties re. addiction

Legality and illegality of opiate use- Schedule 1 (heroin)

o High abuse potential

o No clinical utility

- Schedule 2 (morphine, oxycodone, fentanyl)

o High abuse potential

o Clinical utility

o Prescription dispensing only, closely monitored

- Schedule 3 (hydrocodone, propoxyphene)

o Lower abuse potential

o Clinical utility

o Prescription only

Withdrawal- Early symptoms

o Watery eyes, runny noes

o Yawning, no appetite

o Anxiety, irritability

o Restlessness, insomnia

o Rapid increase of AC activity

- Longer duration, more severe symptoms

o Tremors

o Hallucinations

o Panic

o Chills and sweating

o Cramps

o Nausea, wretching

**High rate of recidivism

Methadone – agonist but does not have pleasurable effects like heroin

Overdose- Initial symptoms

o Slow, shallow breathing

o Cognitive impairment

o Constricted pupils

o Severe drowsiness

o Cold, clammy skin

- Life Threatening Symptoms

o Vomiting

o Loss of consciousness

o Convulsions

o Coma

o Severe respiratory depression anoxia

4/28/09

Drugs of abuse – illicit or illegal ligands

Major categories of controlled substances- Stimulants

o cocaine

o amphetamines

o designer drugs (ecstasy)

- Depressants

o Barbiturates/BDZs

o Opiates

o PCP/ketamine

- Hallucinogens

o Marijuana/hashish

o Peyote

o LSD

o PCP/ketamine

o Psilocybin

o Designer drugs

- Anabolic steroids

o Androgens

Sources of illicit drugs

- synthesis

o diversion from regulated sources

o extraction/modify/purify

- Nature

Drug Enforcement- Federal (sets the standards others follow) Under FBI

o DEA (justice): concentrates on trafficking (international and interstate), diversion,

elimination of foreign growers

o AFT (Treasury): concentrates on domestic production, growers, theoretical “revenue”

sources

- State

o DPS: involves all levels, including low-level dealers and users

- County

o Sheriff: all levels, including low-level dealers and users

- Local

o Police: all levels, including low-level dealers and users

o

Federal Drug Laws- Formal scheduling – The controlled substances Act (CSA;1970) places all substances which

were in some manner previously regulated under existing federal law into one of the five

schedules

1) Potential for abuse

2) Medical uses

3) Safety or dependence liability

Federal Drug Schedules

- Schedule I (heroin, LSD, marijuana, methagualone)

o High potential for abuse

o No currenly accepted medical use

o Lack of accepted safety for use

- Schedule II (morphine, cocaine, methadone, hydrcodone) **tightly regulated

prescriptions

o High potential for abuse

o Currently accepted medical use

o May lead to severe psychological or physical dependence

- Schedule III (anabolic steroids, codeine/hydrocodone, most barbiturates)

o Potential for abuse

o Currently accepted medical use

o Moderate or low physical dependence

- Schedule IV (ex BDZ and anxiolytics)

o Low potential for abuse

o Currently accepted medical use

o Limited physical or psychological dependence

- Schedule V (cough syrup with codeine

o Low potential for abuse

o Currently accepted medical use

o Limited physical or psychological dependence

Variability in enforcement I

- stimulants

o caffeine – none

o nicotine – no sales to minors, smoking bans

o cocaine – schedule II

o amphetamines – schedule II

o designer drugs – schedule I

- depressants

o EtOH – no sales to minors; driving prohibitions

o Opiates – schedule I, II, III, IV, or V

o Barbiturates – Schedule II, III, or IV

o BDZs – schedule IV

o Methaqualone – schedule I

- Hallucinogens

o Designer drugs – Schedule I

o LSD – Schedule I

o Pyote – Schedule I

o Psilocybin – Schedule I

o Marijuana – Schedule I

o PCP – Schedule I

o Ketamine – Schedule III

- Anabolic steroids – Schedule III

Stimulants

- health risks

o sudden arrythmias, etc. leading to cardiac failure risk of acute psychosis with

high doses/chronic use perceived subjective superiority in performance.

DOES NOT match objective measure

- Physical dependence

o Strong risk

o Once developed, physical withdrawal begins within hours after last does

o Withdrawal less severe than opiates

- Psychological dependence

o Stong risk

o Recidivism high for former users (as high or higher than for opiates)

Hallucinogens

- Health Risks

o Multiple reports of mental health problems (can unmask borderline or

developing problems)

o Bad trips, flashbacks

o Substantial risk of obtaining high dose/erroneous substance

- Physical dependence

o None substantiatesd

- Psychological dependence

o Can develop for piperidine dirivitives (PCP, ketamine, etc.) unlikely for others

- Footnote:

o Original medical model to manage hallucinogenic use suggested

recreational/spiritual clinics, with controlled set, setting and dose of known

compounds

o Cf. early works of Richard Alpert, Timothy Leary, Sashatchewan psychiatric

model, et al. treatment of alcoholism, etc.

Opiates

- Health risks

o Overdoes – potentially fatal coma, respiratory depression, emesis

o HIV and other serology – related risks of drug injection

o Malnutrition possible due to severe appetite suppression (coupled with GI

motility reduction)

o Issues related to contaminants/cuts/dose and purity

o Withdrawal related to categories below

- Physical dependence

o Strong risk

o Once developed, physical withdrawal begins within hours after last dose

- Psychological dependence

o Strong risk

o Recidivism high for former users

Other depressants (ETOH, BDZs, barbiturates)

- Health Risks

o Overdose – potentially fatal coma, respiratory depression, emesis (vomiting)

o Issues related to contaminants/cuts/dose and purity

- Physical dependence

o Strong risk

o Once developed, physical withdrawal begins within hours after last dose

o Withdrawal less severe than for opiates

o Psychological dependence

o Strong risk

o Recidivism high for former users (as high or higher than for opiates)

Cannabis (dronabinol is synthetic)

- Health risks

o Smoking related respiratory problems (can be more severe than those for

tobacco, need not be)

o Mild immunosuppression (stabilizes with chronic use)

o Problems associated with adulterants, herbicides, etc

- Physical dependence

o None substantiates

- Psychological dependence

o Varies tremendously by individual

- Potential clinical uses

o Antiemetic/nausea suppressant (chemotherapy)

o Relief of ocular pressure in glaucoma

o Anxiolytic

Cannaboid receptors

Receptor CB1 CB2

Tissue expressing CNS (hippocampus; ctx;

basal ganglia; cblm) rarer in

periphery ()lung; vascular

tissue; testis; uterus

Immune system cells

Endogenous AGO Anandamide

Selective AGO JWH-015

Non-selective AGO THC

Selective ANT SR 144528

Beta gamma subunints

G-Protein alpha subuning Gi

Incomplete list of other hallucinogenic drugs

Ergot derivatieves

- LSD (synthetic also from morning glories, baby wood rose seeds)

- DMT

- DET

Other “natural” hallucinogens:

- psilocybin – from psilocybe mushrooms

- mescaline (from peyote cacti)

- datura (mixure of atropine, harmaline, cscopolamine from Datura stramonium =

Jimson weed)

Hallucinogenic amphetamines:

- DMO= STP= dimethoxyamphetamine

- MDA

Anabolic steroids

- Health risks

o Immunosuppressant

o Cardiac hypertrophy, leading to cardiac failure

o Acceleration of male balding

o Induction of prostate cancer and other tumors

o Risk of acute psychosis with high doses/chronic use

- Physical dependence

o Not well studied; likely

- Psychological dependence

o Considerable risk

******Final Review******

voltage gated channel blockers

know drugs from last lectures

know the pharmakenetics

concentrate on the most recent drugs and the ones that have been recurrent. Know the

mechanisms from notes. I/V curves may come again.

Neuropharm Final Review

Steroid Hormones

Estrogens

- estradiol

- estriol

- estorone

Androgens

- testosterone

- DHT

Progesterone

- progesterone

Glucocorticoid

Know the estradiol metabolism!!

Gonadal steroid biosynthesis

Biosynthesis of adrenal steroids

Steroid hormones

- birth control pills

o ethinyl estraidol

o norethindrone

- Anti-Estrogens

Know the HHPA Axis

A

4/8/09 7:39 PM

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