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Aging and cholinergic responses in bovine trachealis muscle
Author(s) -
Wills Marsha,
Douglas James S.
Publication year - 1988
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.1476-5381.1988.tb11480.x
Subject(s) - oxotremorine , carbachol , muscarine , pilocarpine , muscarinic acetylcholine receptor , trachealis muscle , endocrinology , chemistry , medicine , methacholine , agonist , muscarinic agonist , receptor , biology , stimulation , biochemistry , neuroscience , respiratory disease , lung , charybdotoxin , nitric oxide , epilepsy
1 The relative potencies of muscarinic agonists on bovine tracheal smooth muscle were unchanged as a consequence of aging and were carbachol > oxotremorine > muscarine > pilocarpine > McNeil A‐343. 2 During aging, the potencies of carbachol, oxotremorine, McNeil A‐343 and pilocarpine, but not muscarine, were reduced. 3 Maximal induced tensions to all the agents studied were reduced as a consequence of age. 4 Irreversible antagonism with benzilylcholine mustard showed that agonist efficacy was significantly reduced during aging. 5 Estimated receptor occupancy at the EC 50 was significantly greater in tracheal tissues from the mature versus immature cows for every agonist studied. 6 The dissociation constants for full agonists (carbachol, oxotremorine and methacholine) were decreased with maturation while the converse was observed with partial agonists (McNeil A‐343, pilocarpine). 7 We conclude that there are significant changes in the properties and coupling of muscarinic receptors during aging. These changes may contribute to the reduced airway reactivity seen in vivo.