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Propylbenzilylcholine mustard is selective for rat heart muscarinic receptors having a low affinity for agonists
Author(s) -
Christophe Jean,
Neef Philippe,
Robberecht Patrick,
Waelbroeck Magali
Publication year - 1986
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1986.tb09471.x
Subject(s) - muscarinic acetylcholine receptor , antagonist , receptor , gtp' , agonist , muscarinic antagonist , chemistry , biophysics , binding site , pharmacology , biochemistry , biology , enzyme
1 Propylbenzilylcholine mustard (PrBCM), an irreversible muscarinic antagonist, inactivated receptors with a low affinity for agonists faster than those with a high affinity in rat heart membranes. This result was obtained using either: (a) a low ionic strength buffer (allowing heterogeneity among antagonist binding sites, (b) the same buffer enriched with GTP, or (c) a high ionic strength buffer (where antagonists showed similar binding characteristics to all receptors). 2 These data suggest either that PrBCM is a ‘selective’ antagonist which detects conformational differences between low and high affinity receptors, or that the agonist affinity of cardiac muscarinic receptors is determined, in part, by the relative concentrations of receptor and GTP binding protein.