The Serotonergic System

Question 1

What does this consist of?

Answer 1

9 raphe nuclei in the brain stem, with diffuse projections to the different part of the brain

Question 2

Where do the projections happen?

Answer 2

Descending projections to the cerebellum and spinal cord - pain

Ascending projections towards locus coeruleous

project throughout the cerebral cortex

Question 3

What are raphe neurons?

Answer 3

Fire during wakefulness but quiet during sleep

Question 4

What is this system involved in?

Answer 4

Mood
sleep
pain
emotion
appetite

Question 5

How is serotonin synthesised?

Answer 5

Tryptophan hydroxylase converts Tryptophan (from bananas, milk) - rate limiting step) to 5-HTP - which is converted to serotonin through aromatic amino acid decarboxylase

Question 6

Link between tryptophan and mood

Answer 6

Depletion diet- method of experimentally inducing depressive data

Enrichment - improving mood

Question 7

How is serotonin reuptaken / metabolised?

Answer 7

Signal terminated by reuptake by serotonin transporters (SERTS) on presynaptic membrane - degraded by MAOs in the cytoplasm (destroying left overs)

Question 8

What drugs affect serotonin release and reuptake?

Answer 8

Fluoxetine (prozac) blocks reuptake of serotonin (SSRIs) - antidepressant

Fenfluramine causes the release of serotonin and inhibits its reuptake (used to be used as a appetite suppressant, banned for heart problems)

MDMA - ecstasy causes noradrenaline and serotonin transports to run backwards releasing neurotranmitter into synapse, reverse to normal job, drug of abuse

Monoamine oxidate inbitiors - boost serotonin