Serotonin Flashcards
1
Q
Source
A
Tryptophan==> 5 hydroxy 1 tyryptophan==> serotonin
2
Q
Rate limiting steps
A
availability of tryptophan
3
Q
Synthesis enzymes
A
tryptophan hydroxylase
4
Q
Breakdown enzymes
A
MAO
-preferably MAO A
5
Q
Breakdown product
A
5-hydroxyindoleacetic acid (5- HIAA)
6
Q
Reuptake
A
Serotonin reuptake channel (TCAs, SSRIs inhibit this)
7
Q
Function
A
Mood, perception of pain, feeding, sleep wake cycle, motor activity, sexual behaviour and temperature regulation
8
Q
Receptors
A
- 14 known subtypes of serotonin receptors
- All except 5-HT3 are G-coupled receptors
9
Q
5 HT3
A
-predominantly in the gut, associated with motility
10
Q
5 HT 1A
A
Gi coupled postsynaptic receptor
- antidepressant response (agonist)
- anxiolytics (partial agonist)
- sexual behaviour
11
Q
5-HT1B receptors
A
- Gi coupled presynaptic
- Aggression
12
Q
5-HT1D
A
- Gi coupled, both presynaptic and post-synaptic
- antimigraine (antagonist)
13
Q
5-HT2 receptors
A
- phospholipase C coupled
- post-synaptic
- 5HT2A antagonism leads to antipsychotic response (atypicals) and sedation
- LSD causes 5-HT2A stimulation- agonist/partial agonist
- down regulation noted after antidepressant treatment/ECT2orking memory
- also seen in platelets and smooth muscles
- 5HT2B stimulation may produce cardiac valvular fibrosis (dexfenfluramine)
- 5 HT2c- anxiogenic and anorexic effect (agonists)
14
Q
5-HT6
A
- may be involved in antidepressant action
- antagonism
15
Q
5-HT7
A
-regulation of circadian rhythm
