This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal tract, Subject name: Pharmacology
A 56-year-old woman has nausea due to chemotherapy for breast cancer. Droperidol is effective in reducing nausea because it blocks wof 
Select and explain. 
A. 5-HT 2 receptors in the CTZ, B. Glucocoicoid receptors in the vomiting center, C. Dopamine receptors in the CTZ, D. ACh receptors in the periphery
C: Dopamine receptors in the CTZ
Answer: C: Dopamine receptors in the CTZ 
Explanation: NEUROLEPTICS The older neuroleptics(phenothiazines, haloperidol) are potent antiemetics; act by blocking D2 receptors in the CTZ; antagonize apomorphine induced vomiting and have additional antimuscarinic as well as H1 antihistaminic propey. They have broad spectrum antiemetic action effective in: (a) Drug induced and postoperative nausea and vomiting (PONV). (b) Disease induced vomiting: gastroenteritis, uraemia, liver disease, migraine, etc. (c) Malignancy associated and cancer chemotherapy (mildly emetogenic) induced vomiting. (d) Radiation sickness vomiting (less effective). (e) Morning sickness: should not be used except in hyperemesis gravidarum. Ref:- kd tripathi; pg num:-664