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Regional heterogeneity of endothelium‐dependent vasodilatation in the rabbit kidney.
Author(s) -
Cairns H S,
Rogerson M E,
Westwick J,
Neild G H
Publication year - 1991
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1991.sp018558
Subject(s) - vasodilation , endothelium derived relaxing factor , prostacyclin , endothelium , acetylcholine , sodium nitroprusside , endocrinology , medicine , chemistry , renal function , renal circulation , kidney , efferent , nitric oxide , renal blood flow , afferent
1. Regional heterogeneity of endothelial function exists but its role in the local regulation of vascular tone is uncertain. This heterogeneity may be very important in the control of the glomerular filtration rate (GFR) in which the differential tone in the afferent and efferent arterioles is crucial. 2. When an endothelium‐independent vasodilator, prostacyclin (PGI2) or nitroprusside, was infused into anaesthetized rabbits there were dose‐dependent falls in both mean arterial pressure (MAP) and GFR; PGI2 (0.4 nmol kg‐1 min‐1) altered MAP and GFR by ‐18.5 +/‐ 3.6% (mean +/‐ S.E.M.) and ‐37.7 +/‐ 13.3% respectively and nitroprusside (30 nmol kg‐1 min‐1) by ‐29.7 +/‐ 3.1% and ‐67.0 +/‐ 2.4%. In contrast infusion of an endothelium‐dependent vasodilator, acetylcholine (ACh) or substance P, produced dose‐dependent decreases in MAP but dose‐dependent increases in GFR; ACh (10 nmol kg‐1 min‐1) ‐15.1 +/‐ 2.0% and +43.8 +/‐ 16.5% and substance P (30 nmol kg‐1 min‐1) ‐18.7 +/‐ 1.9% and +45.3 +/‐ 23.1% respectively. The effects of endothelium‐dependent and independent vasodilators on GFR was significantly different (p less than 0.005). 3. Simultaneous administration of indomethacin, Methylene Blue or NG‐monomethyl‐L‐arginine (L‐NMMA), inhibitors of cyclo‐oxygenase and endothelium‐derived relaxing factor (EDRF) respectively, attenuated or reversed the effect of ACh (10 nmol kg‐1 min‐1) on MAP and GFR. 4. These data suggest that endothelium‐dependent vasodilatation in the kidney has a heterogeneous effect on the renal microvasculature, exerting a preferential effect on afferent glomerular arterioles and thereby preserving GFR despite the fall in MAP.(ABSTRACT TRUNCATED AT 250 WORDS)