This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autacoids, Subject name: Pharmacology
[{'content': 'The following 5-HT receptor is not a G-protein coupled receptor \nSelect and explain. \nA. 5-HT1, B. 5-HT2, C. 5-HT3, D. 5-HT4', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Mech of action:- All 5-HT receptors (except 5-HT3) are G protein coupled receptors which function through decreasing (5-HT1) or increasing (5-HT4, 5-HT6, 5-HT7) cAMP production or by generating IP3/ DAG (5-HT2) as second messengers. The 5-HT3 is a ligand gated cation (Na+,K+) channel which on activation elicits fast depolarization. Ref:- kd tripathi; pg num:-171', 'role': 'assistant'}]