This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Histamine, 5-HT and PGs, Subject name: Pharmacology
Most impoant receptor involved in chemotherapy induced vomiting is: 
Select and explain. 
A. Histamine H1 receptor, B. Serotonin 5-HT3 receptor, C. Dopamine D2 receptor, D. Opioid m receptor
B: Serotonin 5-HT3 receptor
Answer: B: Serotonin 5-HT3 receptor 
Explanation: -5HT3 receptors are present in CTZ and are involved in chemotherapy induced vomiting. -Antagonist of this receptor like ondansetron is drug of choice for chemotherapy induced vomiting.