Methacholine acts at which receptor?
(A) M1 (B) M2 (C) M3 (D) M4
(B) Ans: B. M2Methacholine is an M2 receptor agonist.ParameterM1M2M3Agonists (Relatively selective)Oxotremorine, MCN-343AMethacholineBethanecholAntagonists (Relatively selective)Pirenzepine, TelenzepineMethoctramine, TripitramineDarifenacin, Solifenacin