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: Pharmacology
[{'content': 'Effects mediated by H1 histamine receptor include: \nSelect and explain. \nA. Inhibition of gastric acid secretion, B. Induction of hepatic cytochrome P450 enzymes, C. Maintenance of a wakeful state, D. Vasoconstriction of arterioles', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Sedation occurs with those drugs that are potent antagonists of the H1-histamine receptor, including chlorpromazine, olanzapine, quetiapine\xa0and clozapine.\nHistamine\xa0H1\xa0receptors\xa0mediate\xa0many\xa0pathological processes, including allergic rhinitis, atopic dermatitis, conjunctivitis, urticaria,\xa0bronchoconstriction,\xa0asthma\xa0and\xa0anaphylaxis. Moreover, histamine\xa0stimulates\xa0the\xa0parietal\xa0cells\xa0in\xa0the\xa0stomach,\xa0causing\xa0an increase in acid secretion via the activation of H2 receptors.\u200b\nReference: Lippincott Illustrated Reviews: Pharmacology Wolters Kluwer Sixth Edition page no 150,394\u200b', 'role': 'assistant'}]