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Media type:
E-Article
Title:
Chronic administration of angiotensin II (AngII) to rats consuming a high salt diet causes mesenteric vasoconstriction by increasing sympathetic tone
Contributor:
Kuroki, Marcos Takuya;
Guzman, Pilar Ariza;
Fink, Gregory D;
Osborn, John W
Description:
<jats:p>We previously reported that AngII induced hypertension in rats consuming a high salt diet is accompanied by a sustained decrease in mesenteric vascular conductance (MVC). We tested the hypothesis that this vasoconstrictor response is mediated by increased sympathetic tone. Rats (n=5) were fed a high (2%) NaCl diet and instrumented for measurement of mean arterial pressure (MAP) and superior mesenteric artery blood flow (SMABF) during 4 days of control, and 14 days of AngII infusion (150ng/kg/min, sc). The contribution of sympathetic tone to MAP and MVC (SMABF/MAP) was assessed during control, and days 3, 7, and 13 of AngII by ganglionic blockade (hexamethonium; 20mg/kg, iv). MAP increased from a control level of 102±2 mmHg to 133±4, 141±4, and 140±12 on days 3, 7, and 13 of AngII. MVC decreased from 0.108±0.008 mL/mmHg<jats:sup>·</jats:sup>min during control to 0.065±0.004, 0.076±0.009, and 0.09±0.01 over the same time course. The decrease in MAP to ganglionic blockade was similar during control (−39±3) and on Day 3 (−37±12), but then increased significantly on Day 7 (−68±8) and Day 13 (−81±12) of AngII. The increase in MVC to ganglionic blockade was 0.04±0.01 during control and was 0.01±0.01 on Day 3, but then increased on Day 7 (0.06±0.01) and Day 13 (0.064±0.007) of AngII. We conclude that mesenteric vasoconstriction in AngII‐salt induced hypertension is mediated, in part, by a delayed increase in sympathetic tone (<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="DDBJ/EMBL/GenBank" xlink:href="HL076312">HL076312</jats:ext-link>).</jats:p>