Serotonin is a derivative of

(A) Tryptophan # SEROTONIN (5-hydroxytryptamine, 5 HT), produced from tryptophan is important in mere impulse transmission (neurotransmitter)> It regulates sleep, behaviour, blood pressure etc.> Hydroxylation of tryptophan to 5-hydroxytryptophan is catalyzed by liver tyrosine hydroxylase.> Subsequent decarboxylation forms serotonin (5-hydroxytryptamine), a potent vasoconstrictor and stimulator of smooth muscle contraction.> Catabolism of serotonin is initiated by monoamine oxidase (MAO) catalyzed oxidative deamination to 5-hydroxindoleacetate, which humans excrete in their urine (2-8 mg/d)> The psychic stimulation that follows administration of iproniazid is attributed to its ability to prolong the action monoamine oxidase> Serotonin or 5-hydroxytryptamine (5 HT) is a neurotransmitter, synthesized from tryptophan.> Normally, about 1 % of tryptophan is converted to serotonin> The production of 5HT occurs in the target tissues.