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Differential effects of hydroxocobalamin on NO‐mediated relaxations in rat aorta and anococcygeus muscle
Author(s) -
Rajanayagam M.A.S.,
Li C.G.,
Rand M.J.
Publication year - 1993
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.1476-5381.1993.tb13429.x
Subject(s) - hydroxocobalamin , muscle relaxant , endothelium derived relaxing factor , acetylcholine , papaverine , chemistry , vasodilation , aorta , nitric oxide , vascular smooth muscle , cholinergic , muscle relaxation , endocrinology , medicine , pharmacology , smooth muscle , biochemistry , cyanocobalamin , vitamin b12
In rat aortic rings, hydroxocobalamin (10–30 μ m ) produced concentration‐dependent reductions of the relaxant action of nitric oxide (NO) and the endothelium‐dependent, NO‐mediated, relaxant action of acetylcholine. In anococcygeus muscles, hydroxocobalamin (10–30 μ m ) reduced but also prolonged, NO‐induced relaxations, but had no effect on non‐adrenergic, non‐cholinergic‐mediated relaxations. Hydroxocobalamin had no effect on the NO‐independent relaxant action of papaverine in either tissue. It is suggested that hydroxocobalamin sequesters NO by forming nitrosocobalamin. Nitrosocobalamin did not relax aortic rings, but produced a slowly developing and prolonged relaxation of anococcygeus muscles.