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THE SIZE OF THE HYDROXYL GROUP AND ITS CONTRIBUTION TO THE AFFINITY OF ATROPINE FOR MUSCARINE‐SENSITIVE ACETYLCHOLINE RECEPTORS
Author(s) -
BARLOW R.B.,
RAMTOOLA SHENAZ
Publication year - 1980
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.1476-5381.1980.tb10905.x
Subject(s) - muscarine , methiodide , atropine , acetylcholine , chemistry , receptor , muscarinic acetylcholine receptor , acetylcholine receptor , stereochemistry , endocrinology , biochemistry , biology
1 From measurements of the affinity constants of hydratropyltropine and its methiodide for muscarine‐sensitive acetylcholine receptors in the guinea‐pig ileum, the increment in log K for the hydroxyl group in atropine is 2.06 and in the methiodide it is 2.16. These effects are slightly bigger than any so far recorded with these receptors. 2 The estimate of the increment in apparent molal volume for the hydroxyl group is 1.1 cm 3 /mol in atropine and 1.0 cm 3 /mol in the methobromide. 3 The large effect of the group on affinity may be linked to its small apparent size in water as suggested in the previous paper.