5-hydroxytryptamine (5-HT; serotonin)

Learning objectives ■ 5-hydroxytryptamine (5-HT; serotonin) ■ Biosynthesis of 5-HT ■ Currently perceived signifi cance of 5-HT ■ Clinical signifi cance of 5-HT ■ Release of 5-HT from neurones ■ Termination of action of 5-HT ■ Metabolism of 5-HT ■ 5-HT receptors ■ 5-HT as a neurotransmitter and neuromodulator in the gastrointestinal tract (GIT) Learning objectives Be able to give an account of the occurrence, biosynthesis, release and ■ metabolism of 5-HT. Know the given features of 5-HT release and termination of action of ■ 5-HT at the synapse and the clinical signifi cance for drug action. Read through the formidable and growing list of 5-HT receptor subtypes. ■ Be able to give an account of the occurrence and role of 5-HT in the GIT. ■ 5-hydroxytryptamine (5-HT; serotonin) Originally called serotonin because it was fi rst identifi ed in serum and ■ when injected increases blood pressure. A monoamine. ■ Occurs in platelets and as a neurotransmitter and neuromodulator, ■ notably in the brain and GIT.