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The effects of sodium nitroprusside and 8‐bromo‐cyclic GMP on electrical and mechanical activities of the rat tail artery
Author(s) -
Cheung D.W.,
MacKay M.J.
Publication year - 1985
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.1476-5381.1985.tb09441.x
Subject(s) - sodium nitroprusside , phenylephrine , chemistry , cyclic gmp , sodium , hyperpolarization (physics) , membrane potential , medicine , endocrinology , cyclic guanosine monophosphate , sodium channel , biophysics , guanosine , contraction (grammar) , nitric oxide , biochemistry , biology , stereochemistry , blood pressure , organic chemistry , nuclear magnetic resonance spectroscopy
1 The effects of sodium nitroprusside and 8‐bromo‐guanosine 3′:5′‐cyclic monophosphate (8‐bromocyclic GMP) on the electrical and mechanical activities of the rat tail artery were compared. 2 The inhibitory effects of sodium nitroprusside on the contractions induced by noradrenaline, phenylephrine, KCl and clonidine were mimicked by 8‐bromo‐cyclic GMP. 3 Sodium nitroprusside and 8‐bromo‐cyclic GMP increased the resting membrane potential only in preparations with low initial resting membrane potentials. 4 In tissues previously contracted and depolarized with noradrenaline, KCl and clonidine, both sodium nitroprusside and 8‐bromo‐cyclic GMP caused relaxation without significantly affecting the membrane potential. 5 Both sodium nitroprusside and 8‐bromo‐cyclic GMP abolished neurally‐mediated contractions without any significant effect on the electrical responses. 6 These results suggest that the actions of sodium nitroprusside and 8‐bromo‐cyclic GMP are not related to membrane hyperpolarization or inhibition of membrane excitability.