Effect of l-name on glomerular filtration rate in deep and
superficial layers of the rat kidney.
Treeck, Birte, and Knut Aukland.
Department of Physiology, University of Bergen, Bergen, Norway
APStracts 3:0204F, 1996.
The effect of the NO synthase blocker L-NAME on GFR in outer (OC),
middle (MC), and inner cortex (IC) was studied in anesthetized male
Sprague Dawley rats by the aprotinin method. The filtered amount of
125I and 131I labeled aprotinin injected before and after L-NAME
injection was measured in the same cortical tissue samples after
excising the kidney. Arterial pressure (PA) increased on average by
43 mmHg, whereas renal blood flow (RBF) fell by 26 % after L-NAME,
giving an increase in renal resistance of 92 %. At constant renal
arterial pressure resistance rose by only 39 %, revealing that
autoregulation was responsible for about half of the resistance
increase. Total and zonal GFR showed a small, statistically not
significant increase after L-NAME, wether the renal pressure was
allowed to rise or not. The response varied considerably among
animals, but in each animal the GFR varied proportionately in OC, MC
and IC. We conclude that the vasodilator tone of NO is predominantly
located in postglomerular resistance vessels and is similar in the
three cortical layers.
Received 10 May 1996; accepted in final form 31 October 1996.
APS Manuscript Number F144-6.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996