This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'Histamine acts on? \nSelect and explain. \nA. G protein coupled receptors, B. Ligand gated ion channels, C. Enzyme linked receptors, D. Intracellular recepters', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is'a' i.e., G protein coupled receptorsRef: Principles of medical physiology p.7911Histamine acts on G-protein coupled membrane recePtors : -", 'role': 'assistant'}]