Systemic and renal hemodynamic responses to vascular blockade of vasopressin in conscious dogs with ascites.
A role for arginine vasopressin has been implicated in the compensatory control of arterial blood pressure in several animal models with reported increases in plasma levels of arginine vasopressin. A threefold elevation in plasma vasopressin has been reported in conscious dogs following constriction of the inferior vena cava. In the present study, infusion of the arginine vasopressin antagonist [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid), 2-O-methyltyrosine] Arg8-vasopressin into conscious dogs with chronic caval constriction did not decrease mean arterial blood pressure. However, the dose of infused antagonist completely blocked the pressor response to 2 micrograms of exogenous vasopressin. Also the antagonist produced no effect on heart rate, plasma renin activity, or urinary volume and electrolyte excretions. A slight, transient increase (P less than or equal to 0.05) was observed in creatinine clearance and in PAH clearance following antagonist infusion, suggesting a possible decrease in renal vascular resistance. These data suggest that the direct vasoconstrictor actions of vasopressin contribute minimally, if at all, to blood pressure maintenance following chronic caval constriction. Alternatively, blockade of endogenous vasopressin receptors at the level of peripheral arterioles may have resulted in no depressor response due to a masking of this response by other compensatory hormonal and neural pressor systems.
Vari
R C
RC
Freeman
R H
RH
Davis
J O
JO
Sweet
W D
WD
D000818:Animals; D001127:Arginine Vasopressin / Q000031:analogs & derivatives* / Q000494:pharmacology; D001201:Ascites / Q000503:physiopathology; D004285:Dogs; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D011945:Receptors, Angiotensin / Q000187:drug effects*; D011956:Receptors, Cell Surface / Q000187:drug effects*; D017483:Receptors, Vasopressin; D012079:Renal Circulation / Q000187:drug effects*; D012083:Renin / Q000097:blood; D012964:Sodium / Q000378:metabolism; D014661:Vasoconstriction / Q000187:drug effects; D014667:Vasopressins / Q000502:physiology; D014682:Vena Cava, Inferior / Q000502:physiology
D011945:Receptors, Angiotensin; D011956:Receptors, Cell Surface; D017483:Receptors, Vasopressin; D014667:Vasopressins; D001127:Arginine Vasopressin; C025043:vasopressin, 1-(1-mercaptocyclohexaneacetic acid)-2-(O- methyl-L-tyrosine)-8-L-arginine-; D012964:Sodium; D012083:Renin