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Calcium antagonist affinity for adrenergic and cholinergic receptors in rabbit urinary bladder
Author(s) -
Malkowicz S. Bruce,
Wein Alan J.,
Levin Robert M.
Publication year - 1985
Publication title -
neurourology and urodynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 90
eISSN - 1520-6777
pISSN - 0733-2467
DOI - 10.1002/nau.1930040211
Subject(s) - diltiazem , verapamil , muscarinic acetylcholine receptor , receptor , antagonist , pharmacology , cholinergic , adrenergic receptor , endocrinology , medicine , calcium , detrusor muscle , urinary bladder
Calcium antagonists have the ability to relax vesical smooth muscle in vitro and in vivo. The presumed mechanism of action is through the inhibition of calcium translocation, yet these agents have also been shown to bind to several different pharmacological receptors. By employing radioligand binding assays, the affinity of verapamil and diltiazem for several receptor populations in the rabbit detrusor was studied. Verapamil and diltiazem displayed binding affinities for receptor populations in the following order: alpha 1 ‐ and alpha 2 ‐ adrenergic > muscarinic cholinergic > beta‐adrenergic. In all instances verapamil affinity was greater than that of diltiazem. The relatively high Ic 50 's for both muscarinic and beta receptors indicate that the interactions of verapamil and diltiazem with these receptors are of little physiological significance.