This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Pharmacology
Emesis receptor is 
Select and explain. 
A. 5HT1, B. 5HT2, C. 5HT3, D. 5HT4
C: 5HT3
Answer: C: 5HT3 
Explanation: ANSWER: (C) 5HT3REF: Goodman Gillman manual of pharmacology and therapeutics 2008 edition, page 646Iheprocessofnauseaandvomiting appears to be coordinated by a central emesis center in the lateral reticular formation of the mid-brainstem adjacent to both the chemoreceptor trigger zone (CTZ) in the area postrema (AP) at the bottom of the fourth ventricle and the solitary tract nucleus (STN) of the vagus nerve.The lack of a blood-brain barrier allows the CTZ to monitor blood and cerebrospinal fluid constantly for toxic substances and to relay information to the emesis center to trigger nausea and vomitingThe CTZ has high concentrations of receptors for serotonin (5-HT3), dopamine (D2), and opioids, while the STN is rich in receptors for enkephalin, histamine, and ACh, and also contains 5-HT3 receptors.The most effective agents for chemotherapy-induced nausea and vomiting are the 5-HT3 antagonists and metoclopramidePharmacological view of emetic stimuli