Resting cardiovascular status and vasodilator function in a vasopressin-deficient, hypertensive strain of rat.
OBJECTIVE
To assess resting haemodynamic status and vasodilator responses in normotensive vasopressin-deficient (DI/N) and hypertensive vasopressin-deficient (DI/H) rats.


METHODS
DI/N and DI/H rats were chronically instrumented with pulsed Doppler probes and intravascular catheters and were given 3-min infusions of acetylcholine (56 nmol/kg per min), bradykinin (36 nmol/kg per min) or salbutamol (2.1 nmol/kg per min) in the absence and presence of the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 183 nmol/kg per min) or vasopressin (5 pmol/kg per min), to control for the pressor effects of L-NAME.


RESULTS
The DI/H rats had a higher mean arterial blood pressure, lower hindquarters flow and lower vascular conductance than the DI/N rats. In the two strains of rat the haemodynamic responses to L-NAME, as well as to acetylcholine, bradykinin and salbutamol, in the absence or presence of L-NAME, were similar. In both strains of rat the acetylcholine-induced renal vasodilation was blocked by L-NAME, but bradykinin-induced mesenteric and salbutamol-induced hindquarters vasodilation involved L-NAME-sensitive and L-NAME-insensitive components.


CONCLUSIONS
There is vasoconstriction in the hindquarters but not in renal and mesenteric vascular beds of DI/H rats. Vasodilator function is not necessarily impaired in congenital hypertension.
Gardiner
S M
SM
Department of Physiology and Pharmacology, University of Nottingham Medical School, Queen's Medical Centre, UK.
March
J E
JE
Kemp
P A
PA
Bennett
T
T
D000109:Acetylcholine / Q000494:pharmacology; D000420:Albuterol / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001920:Bradykinin / Q000494:pharmacology; D004195:Disease Models, Animal; D006439:Hemodynamics / Q000187:drug effects; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D011863:Radioimmunoassay; D051381:Rats; D014664:Vasodilation / Q000187:drug effects; D014667:Vasopressins / Q000097:blood / Q000172:deficiency*
D014667:Vasopressins; D000109:Acetylcholine; D000420:Albuterol; D001920:Bradykinin