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THE IRREVERSIBLE BINDING OF ACETYLCHOLINE MUSTARD TO MUSCARINIC RECEPTORS IN INTESTINAL SMOOTH MUSCLE OF THE GUINEA‐PIG
Author(s) -
ROBINSON D.A.,
TAYLOR J.G.,
YOUNG J.M.
Publication year - 1975
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.1476-5381.1975.tb07372.x
Subject(s) - muscarinic acetylcholine receptor , acetylcholine , muscarinic acetylcholine receptor m5 , carbachol , muscarinic acetylcholine receptor m3 , muscarinic acetylcholine receptor m2 , chemistry , acetylcholine receptor , muscarinic acetylcholine receptor m1 , agonist , receptor , medicine , endocrinology , muscarinic agonist , biochemistry , pharmacology , biology
1 Acetylcholine mustard ( N ‐2‐chloroethyl‐ N‐ methyl‐2‐acetoxyethylamine), a potent muscarinic agonist, binds virtually irreversibly to muscarinic receptors in longitudinal muscle strips from guinea‐pig small intestine, as shown by the inhibition of the binding of [ 3 H]‐propylbenzilylcholine mustard ([ 3 H]‐PrBCM), an affinity label for the muscarinic receptor. 2 A value for the apparent binding affinity of acetylcholine mustard and a value for the rate constant for the receptor alkylation reaction have been deduced from the rate of onset of the inhibition of [ 3 H]‐PrBCM binding. 3 The kinetic constants obtained may refer largely to the interaction between acetylcholine mustard and the desensitized receptor. 4 At high concentrations acetylcholine mustard practically abolishes the contractile response to carbachol. At these concentrations acetylcholine mustard appears to have multiple actions on the tissue.