Faculty Collaboration Database

Nitric oxide in the renal medulla protects from vasopressin-induced hypertension. Hypertension 2000 Mar;35(3):740-5

Date

03/18/2000

Pubmed ID

10720588

DOI

10.1161/01.hyp.35.3.740

Scopus ID

2-s2.0-4243704027 (requires institutional sign-in at Scopus site)   44 Citations

Abstract

In the present study, we assessed whether activation of the nitric oxide (NO) system within the renal medulla could serve as a buffer against the chronic hypertensive effects of arginine vasopressin (AVP). NO concentration in the renal medulla of Sprague-Dawley rats was measured with in vivo microdialysis/oxyhemoglobin NO trapping. The results showed that medullary interstitial [NO] was increased after 2 hours of AVP infusion and remained elevated even after 10 days (by 62+/-8% and 42+/-13%, respectively). Western blot analysis showed that 2 days of AVP infusion was insufficient to increase protein expression of any of the NO synthase (NOS) isoforms, but after 10 days of AVP infusion, endothelial NOS expression was significantly increased in the inner medulla with no significant changes in noninducible NOS and inducible NOS levels. When renal medullary NOS enzyme activity was blunted with a nonpressor dose of N(G)-nitro-L-arginine methyl ester (75 microg. kg(-1). h(-1)) that was chronically infused locally into the renal medulla, intravenous AVP infusion (which was shown earlier to be subpressor in chronic studies) produced a sustained elevation in arterial pressure (from 107+/-2 to 121+/-2 mm Hg). These data indicate that chronic elevations in plasma AVP enhance renal medullary endothelial NOS protein expression, which enables sustained elevations of NO concentrations in this region of the kidney to buffer the hypertensive effects of AVP.

Author List

Szentiványi M Jr, Park F, Maeda CY, Cowley AW Jr

Author

Allen W. Cowley Jr PhD Professor in the Physiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Arginine
Arginine Vasopressin
Blood Pressure
Endothelium, Vascular
Enzyme Inhibitors
Hypertension, Renal
Infusions, Intravenous
Kidney Medulla
Male
NG-Nitroarginine Methyl Ester
Nitric Oxide
Nitric Oxide Synthase
Nitric Oxide Synthase Type III
Rats
Rats, Sprague-Dawley
Renal Agents
Renal Circulation