Characterization of subtype of propylbenzilylcholine mustard (PrBCM)-sensitive and -resistant muscarinic cholinoceptors in guinea pig ileal muscle.

The subtype of propylbenzilylcholine mustard (PrBCM)-sensitive and -resistant muscarinic cholinoceptors in guinea pig ileal muscle was examined using four selective muscarinic antagonists, pirenzepine, AF-DX 116, himbacine and 4-DAMP. The pA2 values of the four antagonists against pilocarpine were not different from their values against carbachol after the treatment with PrBCM and was identified with the values for the m3 subtype. These results suggest that the subtype of PrBCM-sensitive and -resistant muscarinic cholinoceptors in guinea pig ileal muscle is the m3 subtype only and not other subtypes.