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Characterization of the muscarinic receptor subtype involved in phosphoinositide metabolism in bovine tracheal smooth muscle
Author(s) -
Roffel A.F.,
Meurs H.,
Elzinga C.R.S.,
Zaagsma J.
Publication year - 1990
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.1476-5381.1990.tb14697.x
Subject(s) - pirenzepine , muscarinic acetylcholine receptor , methacholine , muscarinic acetylcholine receptor m2 , muscarinic acetylcholine receptor m3 , muscarinic acetylcholine receptor m1 , endocrinology , muscarinic antagonist , antagonist , medicine , biology , receptor , chemistry , lung , respiratory disease
1 The muscarinic receptor subtype involved in the methacholine‐induced enhancement of phosphoinositide metabolism in bovine tracheal smooth muscle was identified by using the M 2 ‐selective antagonist AF‐DX 116 and the M 3 ‐selective antagonist 4‐diphenylacetoxy‐N‐methylpiperidine (4‐DAMP) methobromide, in addition to the M 1 ‐selective antagonist pirenzepine, in a classical Schild analysis. 2 All the antagonists shifted the methacholine dose‐response curve to the right in a parallel and concentration‐dependent fashion, yielding Schild plots with slopes not significantly different from unity. The pA 2 values (6.94, 6.32 and 8.54 for pirenzepine, AF‐DX 116 and 4‐DAMP methobromide respectively) indicate that it is the M 3 (smooth muscle/glandular), but not the M 2 (cardiac) muscarinic receptor subtype, present in this tissue, that mediates phosphoinositide turnover, in accordance with our previous contractile studies. 3 The results provide additional evidence for the involvement of phosphoinositide turnover in the pharmacomechanical coupling between muscarinic receptor stimulation and contraction in (bovine tracheal) smooth muscle.