Antiemetic action is through ?

Ans. is 'a' i.e., .LCTZThe chemoreceptor trigger zone (CTZ) - most impoant.The vestibular systemThe periphery, e.g. distension or irritation of the gut, myocardial infarction, biliary or renal stone.Coical centresVomiting centre and nucleus of tractus solitarius contain muscarinic cholinergic and histamine H1 receptors.CTZ is located in area postrema (outside BBB) and contains Dopamine D2, opioid & serotonine 5-HT3 receptors.So, antiemetic that act on vomiting centre have antimuscarinic and antihistaminic action can allete vomiting from any cause.