Serotonin

It is also known as 5-Hydroxy Tryptamine. It is an indole-ethylamine.
Synthesis:

Mechanism of action:
Seven families of 5-HT receptor sub-types (subscripts 1-7) are there. They act through a variety of cell membrane receptors that include:
1. Six involved G-protein coupled receptors.
2. One uses ligand gated ion channels.

Action:
It acts as a neurotransmitter causing strong inhibitory effect. It acts on chemosensitive endings causing bradycardia and hypotension. It can cause aggregation of platelets. It may cause hyperventilation due to chemoreceptor reflex.

Clinical uses of serotonin analogues:
1. Buspirone (a 5-HT1A agonist) is used as non-benzodiazepine anxiolytic.
2. Sumatriptan can be used in acute migraine and cluster headache.
3. Appetite suppression appears to be caused by the agonist action at 5-HT2C receptors in the central nervous system.
4. Cisapride (a 5-HT4 agonist) was used for gastroesophageal reflux disease and motility disorders.