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Regional haemodynamic effects of vasopressin infusion in conscious, unrestrained, Brattleboro rats
Author(s) -
Gardiner S.M.,
Compton A.M.,
Bennett T.
Publication year - 1989
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.1476-5381.1989.tb11935.x
Subject(s) - vasopressin , vasoconstriction , medicine , endocrinology , vasopressin receptor , vasopressin antagonists , vasodilation , vascular resistance , hemodynamics , mesenteric arteries , bradycardia , antagonist , blood pressure , heart rate , receptor , artery
1 Incremental rates of infusion (0.027–4.0 pmol min −1 ) of exogenous vasopressin were given for 10 min periods to conscious, Brattleboro (i.e. vasopressin‐deficient) rats, which had been chronically instrumented with pulsed Doppler probes and intravascular catheters (to permit assessment of regional haemodynamic changes). 2 There were no significant effects of the two lowest rates of infusion (0.027 and 0.105 pmol min −1 ) but, after 10 min of vasopressin infusion at 0.313 pmol min −1 , superior mesenteric vasoconstriction had occurred unaccompanied by any other changes. Infusion of vasopressin at 0.687 pmol min −1 produced increases in blood pressure and in both mesenteric and hindquarters vascular resistance, but no change in renal vascular resistance or heart rate. These results do not indicate specific interactions between exogenous vasopressin and baroreflex mechanisms to offset the pressor effect of the neuropeptide. 3 The marked bradycardia, hypertension and renal, mesenteric and hindquarters vasoconstriction seen after 10 min infusion of vasopressin at 4.0 pmol min −1 were all abolished 10 min after administration of an antagonist of V 1 ‐receptors ((+)−(CH 2 ) 5 Tyr(Et)DAVP); additional antagonism of V 2 ‐receptors (with the non‐selective antagonist (+)−(CH 2 ) 5 Tyr(Et)VAVP) had no effects on any measured variable. Hence, the present experiments provide no evidence for important vasodilator effects of vasopressin in conscious, Brattleboro rats.