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