Characterization of muscarine receptors in rabbit ciliary body smooth muscle using propylbenzilylcholine mustard.

1. A piece of rabbit ciliary body was mounted in organ bath and used as a test organ containing muscarine receptors. 2. A concentration response curve of carbachol was completely inhibited by a 50 min treatment of the smooth muscle preparation with propylbenzilylcholine mustard(PrBCM; 10(-6) M). This treatment was reported to block PrBCM-sensitive muscarine receptors in intestinal smooth muscle completely. 3. It is suggested that an existance of only PrBCM-sensitive muscarinic receptors, though there are two subtypes of muscarine receptors; PrBCM-sensitive and -resistant ones in intestinal smooth muscles.