title: Effects of verapamil on the binding characteristics of muscarinic receptor subtypes.
abstract: The calcium channel antagonist verapamil inhibited [3H]N-methyl scopolamine ([3H]NMS ) binding to muscarinic receptors from both rat brain cortex, an area rich in M1 receptors, and from pons-medulla, an area rich in M2 receptors. Verapamil reduced the dissociation kinetics of [3H]NMS binding in cortical receptors but had no detectable effects on the dissociation kinetics of receptors from the pons-medulla. These data suggest that receptors from the cortex have an allosteric site which regulates the binding kinetics, whereas receptors from the pons-medulla lack this site.
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008526:Medulla Oblongata / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D010890:Pirenzepine / Q000378:metabolism; D011149:Pons / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*; D014700:Verapamil / Q000494:pharmacology*
chemical_list: D011976:Receptors, Muscarinic; D010890:Pirenzepine; D014700:Verapamil