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Picture from http://www.humanillnesses.com/original/Conj-Dys/Depressive-Disorders.html

Supplemental instruction

Additional review

•Neural synapse•Neurotransmitters

Designed by Pyeongsug Kim ©2010 [email protected]

http://www.humanillnesses.com/original/Conj-Dys/Depressive-Disorders.html

mailto:[email protected]

Picture from http://www.humanillnesses.com/original/Conj-Dys/Depressive-Disorders.html http://www.eregimens.com/regimens/MS_Regimen.htm

SynapseSynapse - The location where a neuron passes its signal to its target cell

Target cell =usually another neuron, a muscle cell, or a gland cell

-A synapse includes… Axon terminals of the presynaptic cell Dendrites of the postsynaptic cell or muscle cell or gland cell. Synaptic cleft

Designed by Pyeongsug Kim, ©2010 www.science-i.com

http://www.humanillnesses.com/original/Conj-Dys/Depressive-Disorders.html

http://www.eregimens.com/regimens/MS_Regimen.htm

http://www.science-i.com/

A :

B :

C:

1. Mitochondria 2.

3. Autoreceptor 4.

5.

6.

7. release NT by___________

8. NT re-uptake pump

Neuron (Presynaptic)

Neuron or cells (Postsynaptic)

Synaptic vesicle

Synaptic cleft

NT receptor

Calcium Channel

exocytosis

C

Neurotransmitter(NT)

Chemical Synapse!



Synaptic Transmission 1.

2.

3.

4.

5.

Action potentials reach at the axon terminal.

VG-Ca2+ channels open.

Ca2+ activates calmodulin.

Calmodulin activates a protein kinase.

Protein kinase promote

fusion and exocytosis of

vesicles.

The presynaptic neuron uses neurotransmitters(NT) to send

the signal across the synaptic cleft.

The NTs diffuse across the cleft to the dendrites of the

postsynaptic cell.Designed by Pyeongsug Kim, ©2010 www.science-i.com


Picture from http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=neurosci&part=A570&rendertype=figure&id=A576


http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=neurosci&part=A570&rendertype=figure&id=A576


If the channel is for Na+

Na+ (enter/ get out of ) the cell.

(EPSP/ IPSP) will occur

In the postnaptic cell……..In the postnaptic cell……..-NTs bind receptor proteins on the dendrites. Cause ion channels open.

If the channel is for K+

K+ (enter/ get out of ) the cell.

(EPSP/ IPSP) will occur

If the channel is for Cl-

Cl- (enter/ get out of ) the cell.

(EPSP/ IPSP) will occur Designed by Pyeongsug Kim, ©2010 www.science-i.com


IPSP

-Inhibitory Postsynaptic Potential from one exposure to neurotransmitter

-The region of negative charge inside

the neuron or positive charge out of

the neuron.

-inhibitinhibit an action potential in the axon.

EPSP

-Exitatoy Postsynaptic Potential from one exposure to neurotransmitter

-The region of positive charge inside

the neuron or negative charge out of

the neuron.

-promotepromote an action potential in the

axon.



EPSP? IPSP?

IPSP

EPSP

IPSP

+ charge? –charge? In? Out?

EPSP



EPSPs and IPSPs summate.

if membrane potential in postsynaptic cell reaches

threshold at the axon hillock, a new AP is generated.

if not, no AP occur.



NeurotranmittersNeurotranmitters1) Acetylcholine1) Acetylcholine-Choline Some CNS neurons(excitatory) Many PNS motor neurons (either excitatory or inhibitory)

-Cholinergic neurons: use acetylcholine as NT

-Somatic neuron :synapses on skeletal muscle :large EPSPs - stimulates muscles to contract

-Preganglionic neuron in both Symp. & ParaSymp.-Postganglionic ParaSymp.

-Curare blocks ACh action

-Cholinergic receptors in the postsynaptic cells



-Cholinergic receptors NicotinicNicotinic - skeletal muscle fibers, autonomic ganglia - Directly bind to channel (Na+ in; followed by K+ out)

EPSP! MuscarinicMuscarinic - binds smooth and cardiac muscle; glands - G-protein; open indirectly adjacent channel (K+ out)

IPSP!



Monoamines act through second messenger.- dopamine

- norepinephrine

- serotonin



Neurotranmitters(monoamines)Neurotranmitters(monoamines)

1)1) Norepinephrine Norepinephrine - catecholamines - works both CNS and PNS -fight-or-flight response -postganglionic Sym.

stimulate cardiac muscle,

cardiac muscle, some glands

Picture from: Dr. Wright Bio6 slide http://www.thecausewayretreat.com/blog/2009/06/fight-or-flight-response/


http://www.thecausewayretreat.com/blog/2009/06/fight-or-flight-response/

Neurotranmitters(Monoamines)Neurotranmitters(Monoamines)2) Dopamine2) Dopamine - Monoamines -Nigrostriatal dopamine system :originates in the substantia nigra :involved in motor control. :Degeneration of this system causes ________________

L-DOPA and MAO inhibitors - Mesolimbic dopamine system :involved in behavior and emotional reward :Most addictions activate this system

Overactivity contributes to _____________

anti-dopamine drugs!

Parkinson's disease

schizophrenia


Neurotranmitters (Monoamines)Neurotranmitters (Monoamines)3) Serotonin3) Serotonin - Involved in regulation of mood, behavior,

appetite andcerebral circulation

- SSRIs (serotonin-specific reuptake inhibitors) - as antidepressants - Prozac, Zoloft

Picture from http://www.humanillnesses.com/images/hdc_0000_0001_0_img0054.jpg


http://www.humanillnesses.com/images/hdc_0000_0001_0_img0054.jpg

Picture from http://www.brookscole.com/chemistry_d/templates/student_resources/0030223180_garrettgrisham/HotTopics/prozac.html


http://www.brookscole.com/chemistry_d/templates/student_resources/0030223180_garrettgrisham/HotTopics/prozac.html

Enteric nervous system (ENS) Enteric nervous system (ENS) -efferent nervous system (PNS)-directly controls the gastrointestinal system-May be considered ANS(Autonomic nervous system)


Glutamic acidGlutamic acid-the most common neurotransmitter in the brain -always excitatory -Receptors that increase the flow of positive ions by opening ion-channels eg) NMDA(or NMDAR) receptor & AMPA receptors LTP (Long-Term Potentiation) ~ crucial to some forms of learning & memory. -concentrated in the cerebral cortex (hippocampus, amygdala, & basal ganglia -When Mg2+ block the NMDA channel, AMPA allows Na+ in. AMPA cause depolarization enough to expel Mg2+. Na+ & Ca2+ in through NMDA. EPSP!!!


GlycineGlycine-makes the post-synaptic membrane more permeable to Cl- ion. Hyperpolarization! (IPSP) -Spinal cord, Brain stem-GlyR (Glycine receptor)-Glycine-gated chloride channels


Tryptophan(serotonin)Tryptophan(serotonin)-Found in both CNS & PNS (enteric nervous system)-regulation of mood, appetite, sleep, muscle contraction, and some cognitive functions including memory and learning.

-the serotonin in the brain is independently synthesized from tryptophan transported across the blood-brain barrier.-Raphe nuclei-5-HT receptors ~ EPSP or IPSP ~G protein-coupled receptors, cAMP(2nd messenger)


Arginine (nitric oxide)Arginine (nitric oxide)-does not bind to surface receptors-readily diffuses across cell membranes-increase cGMP(2nd messenger) -Parasymphethetic neurons Enteric nervous system(ENS)-Relaxation of smooth muscle (=inhibition of smooth muscle contraction)

-vasodilation


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