Faculty Collaboration Database

Angiotensin II AT1 receptors preserve vasodilator reactivity in skeletal muscle resistance arteries. Am J Physiol Heart Circ Physiol 2001 May;280(5):H2196-202

Date

04/12/2001

Pubmed ID

11299222

DOI

10.1152/ajpheart.2001.280.5.H2196

Scopus ID

2-s2.0-0035030180 (requires institutional sign-in at Scopus site)   45 Citations

Abstract

Resistance arteries (100-150 microm) were isolated from the gracilis muscle of normotensive Sprague-Dawley rats placed on a high-salt (HS) diet (4.0% NaCl) for 3-7 days. Exposure to the HS diet eliminated vascular relaxation in response to hypoxia (PO2 reduction to 35-40 Torr) and iloprost, a stable analog of prostacyclin. Vasodilator responses were restored in arteries isolated from chronically instrumented HS rats receiving a continuous intravenous infusion of either angiotensin II (ANG II; 5-6 ng x kg(-1) x min(-1)) or ANG II plus the AT2 receptor blocker PD-123319 (5 microg x kg(-1) x min(-1)) for 3 days before the isolated vessel studies. In contrast, coinfusion of the AT1 receptor blocker losartan (20 microg x kg(-1) x min(-1)) or coinfusion of both receptor blockers with ANG II eliminated the protective effect of ANG II to restore dilator responses to hypoxia and iloprost. Neither a HS diet nor ANG II infusion affected the dilation of gracilis arteries in response to direct activation of adenylyl cyclase by forskolin, suggesting that the effect of both the HS diet and the ANG II on the vasculature is mediated upstream from second messenger systems. These findings indicate that the protective effect of ANG II to maintain vasodilator reactivity in resistance arteries of rats on a HS diet is mediated via the AT1 receptor subtype.

Author List

Weber DS, Lombard JH

Author

Julian Lombard PhD, MS Emeritus Professor in the Physiology department at Medical College of Wisconsin

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

Angiotensin II
Animals
Antihypertensive Agents
Blood Pressure Determination
Consciousness
Iloprost
Imidazoles
In Vitro Techniques
Losartan
Male
Microcirculation
Muscle, Skeletal
Muscle, Smooth, Vascular
Oxygen
Pyridines
Rats
Rats, Sprague-Dawley
Receptor, Angiotensin, Type 1
Receptor, Angiotensin, Type 2
Receptors, Angiotensin
Renin-Angiotensin System
Sodium, Dietary
Vascular Resistance
Vasoconstrictor Agents
Vasodilation
Vasodilator Agents