w heel r unning a lters s erotonin (5-ht) t ransporter, 5-ht 1a, 5-ht 1b, and a lpha 1 b -a...

25
WHEEL RUNNING ALTERS SEROTONIN (5-HT) TRANSPORTER, 5-HT1A, 5-HT1B, AND ALPHA1B-ADRENERGIC RECEPTOR MRNA IN THE RAT RAPHE NUCLEI Greenwood et al 2005

Upload: jemima-washington

Post on 30-Dec-2015

216 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

WHEEL RUNNING ALTERS SEROTONIN (5-HT)

TRANSPORTER, 5-HT1A, 5-HT1B, AND ALPHA1B-

ADRENERGIC RECEPTOR MRNA IN THE RAT RAPHE

NUCLEI

Greenwood et al 2005

Page 2: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

DEPRESSIONThought to be an overall decrease in serotonin transmission through out the central nervous system.

Antidepressants are designed to reverse this process.

Page 3: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

RAPHESerotonin output center of the

brainThought to be a big source of

action for SSRIsPrevents the reuptake of serotonin

increasing neurotransmissionTreats depression

Page 4: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

PREVIOUS WORK Voluntary wheel running acts as an

antidepressent in models Forced swim Chronic mild stress Learned helplessness

6 weeks wheel running lowers the activity of 5HT neurons in the dorsal raphe nucleus (DRN) during uncontrollable stress Prevents learned helplessness

Page 5: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

M&M Male Fischer F344 rats individually housed 12:12hr light/dark cycle

Lights on at 6AM 1wk acclimatization with locked running

wheels Ad libitum food and water Unlocked wheels for 3 days, 3 wks, 6wks

Page 6: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

WHAT WAS LOOKED AT

Page 7: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

SEROTONIN TRANSPORTER (5-HTT)(SERT)

Pre-synapse

5-HT

5-HTT

Reuptakes 5-HT

Page 8: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

SEROTONIN 1A & 1B RECEPTORS

(5-HT1A & 5-HT1B)

Located on soma, dendrites and axon terminals

Act as auto receptors that inhibit: Synthesis of 5-HT Release of 5-HT

Ultra short loop negative feedback

Page 9: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

Coupled Gp-protein / IP3 / Ca++

Norepinephrine binds

Stimulates Raphe Increases 5-HT output

Alpha1B Adrenergic Receptor

(α1b ADR)

Page 10: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

5-HTT, 5-HT1A, 5-HT1B, Α1B-ADR

In situ hybridization Measures mRNA

levels Assumed there is a

direct correlation with protein

Translation? Binding to

receptors?

What technique was used? Problems with this technique

Page 11: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

WHY WERE THESE 4 THINGS LOOKED AT?

Estimated that all 5HT neurons in raphe contain these things

All of these things can modulate serotonin transmission in the raphe

Page 12: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

Changes in

distance and weight

Page 13: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

Dorsal Raphe Nucleus (DRN) Median Raphe Nucleus (MR)

Page 14: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

5-HTT 5-HT1A 5-HT1B α1b-ADR

Page 15: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

Seritonin transporter mRNA levels (5-HTT)

Relative 5-HTT mRNA levels: integrated optical density

Page 16: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

AS FAR AS 5HTT IS CONCERNED

See a decrease in raphe mRNA

Page 17: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

Alpha 1B Adrenergic Receptor levels (α1b-ADR)

Relative alpha 1b-ADR mRNA levels: Integrated optical density

Page 18: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

Α1B-ADR (NE RECEPTOR)

NE systems are activated by acute exerciseFrom locus ceruleus

The increased NE levels may down regulate receptors

Page 19: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

Seritonin 1B Receptor levels (5-HT1B)

Relative 5-HT1B mRNA levels: Integrated optical density

Page 20: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

5-H

T1B

Page 21: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

5-HT1B

AUTORECEPTOR Trend of decreasing overall Exercise and SSRIs decrease Ventral DRN did show a significant decrease

Selective innervations of certain areas? Caudate putamen Cortex

In a separate study, increased 1B makes rats more anxiety prone suggests an increased capacity to synthesize

presynaptic 5-HT1B receptors and could account for diminished serotonin neurotransmission in learned helplessness (Neumaier JF, et al)

Page 22: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

Relative 5-HT1A mRNA levels: Integrated optical density

Seritonin 1A Receptor levels (5-HT1A)

Page 23: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

5-HT1A autoreceptor Increased after running

More negative feedbackOpposite of antidepressant treatment

Increased AND decreased levels of 5-HT1A have been seen in suicides or depressed subjectsThere’s more to this story

Page 24: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

5-HT1A Learned helplessness(LH) appears to be

dependent on hyperactivation and sensitization of DRN 5-HT neurons. (Takase et al)

LH can also be attenuated by 6wks voluntary wheel running (greenwood)

5-HT1A increasing after 6 weeks may provide a means of protection from LH Possibly other depression models as well

Page 25: W HEEL R UNNING A LTERS S EROTONIN (5-HT) T RANSPORTER, 5-HT 1A, 5-HT 1B, AND A LPHA 1 B -A DRENERGIC R ECEPTOR M RNA IN THE R AT R APHE N UCLEI Greenwood

FURTHER INVESTIGATIONS

Interesting correlation between the time dependent effects of both running and antidepressants6 wks but not 3wks of running

overcomes learned helplessness in shuttle box (Greenwood)