Buspirone acts on:

Ans. (A) 5HT1A(Ref: Goodman and Gilman 13th/234)Drugs acting on serotonergic receptors 5-hydroxytryptamine (serotonin) is synthesized from tryptophan. It acts by activation of several serotonin receptors (5-HT1 to HT7).5-HT1A (presynaptic receptor) modulates the release of serotonin. Partial agonists of this receptor (buspirone, ipsapirone, gepirone) are useful as anti-anxiety drugs.5-HT1B/1D (presynaptic receptor) cause constriction of cranial vessels and agonists at this receptor (sumatriptan, naratriptan) are useful for the treatment of acute migraine attacks.5-HT2A/2C receptor is responsible for most of the direct actions of serotonin. Ketanserin and ritanserin are antagonists at this receptor and are useful as antihypertensive agents. Clozapine and risperidone are atypical antipsychotic agents that act through antagonistic activity at this receptor.5-HT3 receptor is an ionotropic receptor (other 5 HT receptors are GPCRs) and mediates most of the reflex and indirect actions of serotonin. Stimulation of this receptor is responsible for vomiting induced by anticancer drugs. 5-HT3 receptor antagonists like ondansetron are the drug of choice for chemotherapy induced vomiting.5-HT4 receptor is present in GIT and is responsible for increase in peristalsis. Agonists at his receptor (cisapride, tegaserod) are useful as prokinetic agents in the treatment of gastroesophageal reflux disease.