Influence of endothelium-derived relaxing factor on renal microvessels and pressure-dependent vasodilation.
The influence of endothelium-derived relaxing factor (EDRF) on renal microvessels and autoregulation was visualized in vivo, in the split hydronephrotic kidney of rats. EDRF synthesis was inhibited by local administration of 10(-5) M NG-nitro-L-arginine methyl ester (L-NAME). Diameters of arcuate arteries decreased by 17%. In cortical vessels efferent arterioles constricted more (13-16%) than interlobular arteries and afferent arterioles (7-12%). Cortical glomerular blood flow (GBF) decreased by 46% after L-NAME. A similar behavior of blood flow and vascular diameters was also observed in juxtamedullary (JM) arterioles. The responses to acetylcholine but not to sodium nitroprusside were attenuated after L-NAME. After local administration of L-arginine (10(-3) M) diameters of all vessels and GBF increased, vascular responses to L-NAME were blunted. Stepwise reduction of renal perfusion pressure revealed that autoregulation was preserved in cortical vessels after L-NAME. In JM arterioles, which do not autoregulate in female Wistar rats, autoregulation of GBF was enhanced after L-NAME. These data suggest that tonic formation of EDRF influences basal renal hemodynamics to a considerable extent. EDRF may also impair autoregulation of JM glomeruli without disturbing autoregulation of cortical glomeruli.
Hoffend
J
J
First Department of Physiology, University of Heidelberg, Germany.
Cavarape
A
A
Endlich
K
K
Steinhausen
M
M
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D005260:Female; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology*
D009569:Nitric Oxide; D001120:Arginine; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester