This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
[{'content': 'Activation of the following type of receptors present on myenteric neurons by metoclopramide is primarily responsible for the enhanced acetylcholine release and improving gastric motility: \nSelect and explain. \nA. Muscarine M1, B. Serotonergic 5-HT3, C. Serotonergic 5-HT4, D. Dopaminergic D2', 'role': 'user'}, {'content': 'Answer: C \nExplanation: (Ref: KDT 6/e p646, 647) Gastric motility is increased by ACh. Release of this neurotransmitter is enhanced by 5HT4 receptor stimulation and 5HT3 and D2 receptor antagonism.', 'role': 'assistant'}]