Arginine vasopressin-induced renal vasodilation mediated by nitric oxide.
The vasoconstrictor vasopressin has been reported to induce paradoxical local vasodilation in the basilar vasculature through stimulation of the endothelium-derived relaxing factor nitric oxide (NO). We investigated the possibility that at subpressor doses, exogenous arginine vasopressin (AVP) might have a similar effect in the kidney. Ten Inactin-anesthetized rats were infused with sequential doses of AVP from 25 to 6,400 microU/min in 30-min increments. Subpressor infusion resulted in progressive renal vasodilation; renal blood flow (RBF) increased significantly going from 14 +/- 6% above basal at 200 microU/min (p < 0.02) to 27 +/- 5% (p < 0.01) at 1,600 microU/min accompanied by a 24 +/- 5% decrease in renal vascular resistance (RVR). At 6,400 microU/min, blood pressure (BP) increased 29 +/- 6 mm Hg and RVR increased. A second group of 8 rats were first given 10 mg/kg b.w. of the NO synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME) before infusion of AVP. L-NAME increased BP 22 +/- 3 mm Hg (p < 0.001), and decreased RBF 16 +/- 3% (p < 0.005). After L-NAME, no dose of AVP had any further effect on either BP, RBF, or RVR. Continuous infusion of a single subpressor dose of 100 microU AVP resulted in a 26% increase in RBF (from 7.52 +/- 0.68 to 9.49 +/- 0.54 ml/min/g kidney weight, p < 0.001). AVP doubled urinary cyclic guanosine monophosphate excretion, a marker for renal NO synthesis, from 8.51 +/- 1.01 to 17.48 +/- 4.26 pM/min (p < 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)
Rudichenko
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VM
Hypertension and Vascular Research Division, Henry Ford Hospital, Detroit, MI 48202-2689, USA.
Beierwaltes
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WH
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001127:Arginine Vasopressin / Q000494:pharmacology*; D007668:Kidney / Q000098:blood supply* / Q000187:drug effects; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
D001127:Arginine Vasopressin; D009569:Nitric Oxide; D001120:Arginine; D019331:NG-Nitroarginine Methyl Ester