AJP - Regulatory, Integrative and Comparative Physiology, Vol 255, Issue 4 563-R568, Copyright © 1988 by American Physiological Society
Renal hemodynamics and vascular reactivity in canine DOCA-salt hypertension
J. L. Goering, P. C. Raich and B. G. Zimmerman
Department of Pharmacology, University of Minnesota, Minneapolis 55455.
Because of the potential role that the kidney may play in
deoxycorticosterone acetate (DOCA)-salt hypertension, changes in renal
blood flow, renal vascular reactivity, and renal adrenergic vascular tone
were followed in the conscious instrumented dog. DOCA-salt was administered
daily after obtaining control measurements. Systemic mean arterial blood
pressure (MAP) was monitored with an indwelling catheter, renal blood flow
(RBF) was measured electromagnetically using an implanted blood flow probe,
and drugs were administered intrarenal arterially through an indwelling
renal artery catheter. During the first week of DOCA-salt administration
MAP increased from 106 +/- 3 to 118 +/- 2 mmHg and at week 2 to 123 +/- 2
mmHg (P less than 0.01). RBF increased from 275 +/- 32 to 336 +/- 34 during
week 1 (P less than 0.05) and to 324 +/- 29 ml/min during week 2. The log
ED50 of norepinephrine administered intra-arterially decreased from 1.66
+/- 0.114 to 1.48 +/- 0.091 and 1.41 +/- 0.067 ng/ml (P less than 0.05),
and of angiotensin II from 2.58 +/- 0.072 to 2.31 +/- 0.09 (P less than
0.05) and 2.38 +/- 0.05 pg/ml, during weeks 1 and 2, respectively. There
was, however, no increase in adrenergic vascular tone as determined by the
change in RBF obtained with the intra-arterial infusion of
alpha-adrenoceptor antagonists. These experiments indicate that RBF is not
compromised in canine DOCA-salt hypertension, and renal adrenergic tone is
no greater in the hypertensive than in the normotensive control period.
