M2, M3, and M4 muscarinic receptors are expressed in the guinea pig gallbladder.
Cabadak H, Cuadra AE, El-Fakahany EE, Kan B. M2, M3, and M4 muscarinic receptors are expressed in the guinea pig gallbladder. J Recept Signal Transduct Res. 2009; 29(1):63-6.