AJP - Renal Physiology, Vol 252, Issue 3 487-F490, Copyright © 1987 by American Physiological Society
Influence of salt on response to nitrendipine by Dahl rat kidney
T. H. Steele and L. Challoner-Hue
We examined the responses to the calcium channel blocker, nitrendipine, of
isolated perfused kidneys from Dahl salt-sensitive (DS) and salt-resistant
(DR) rats that had been stabilized on high- and low-NaCl diets. Blood
pressures of high-salt DS rats exceeded those of the other three groups.
After norepinephrine vasoconstriction sufficient to increase renal vascular
resistance (RVR) by 50%, the superimposition of 10(-5) M nitrendipine
increased the glomerular filtration rate (GFR) of high-salt DS rat kidneys
by 125% over control values but returned the GFR of high-salt DR kidneys
only to control. Nitrendipine superimposition increased the GFR of low-salt
DS and DR rat kidneys by 124 and 40% over control values, respectively, and
partially restored the RVR toward control. Nitrendipine alone, without
norepinephrine, did not affect the GFR or RVR. The persistence within the
DS kidney of an exaggerated glomerular circulatory "rebound" response to
nitrendipine following the development of hypertension suggests the
possibility of a maladaptation of DS kidney cell calcium regulation. The DR
kidney manifests a similar response during salt restriction, but this
disappears on a high-NaCl diet.
