Serotonin (5-HT) is a neurotransmitter that regulates mood, sleep, appetite, and cognitive functions in the CNS.
Function Serotonin (5-HT):
- Regulates mood, appetite, sleep, pain perception, and cognition.
Receptors:
- Multiple subtypes (5-HT1 to 5-HT7) with distinct actions:
- 5-HT1A: mood, anxiety.
- 5-HT2A: hallucinations, platelet aggregation.
- 5-HT3: vomiting center (only ionotropic receptor).
- 5-HT4: GI motility.
Synthesis Pathway:
- Tryptophan (from diet) → 5-Hydroxytryptophan (5-HTP)
- Enzyme: Tryptophan hydroxylase
- 5-HTP → Serotonin (5-HT)
- Enzyme: Aromatic L-Amino Acid Decarboxylase (AADC)
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Drugs:
- SSRIs (fluoxetine), SNRIs (venlafaxine), MAO‑A inhibitors (moclobemide), triptans (sumatriptan) for migraine vasoconstriction.
Clinical Relevance:
- Depression
- Anxiety
- Migraine
- Nausea/vomiting
