Effect of OVLT lesion on AngII‐salt hypertension in the rat

Abstract

We have recently shown that lesion of the organum vasculosum of the lamina terminalis (OVLT) abolishes the hypertensive effects of chronic angiotensin II (AngII) in rats consuming a normal salt diet (0.4% NaCl). While these results support the idea that the OVLT plays an important role in AngII‐induced hypertension, the OVLT has also been suggested as a major sodium sensor in the brain, and the hypertensive effects of AngII are exacerbated by high salt intake. The objective of this study was to investigate the role of the OVLT during AngII‐induced hypertension concurrent with a high salt diet. Male Sprague‐Dawley rats underwent sham (OVLTsham; n = 7) or OVLT lesion (OVLTx; n = 5) and were placed on a high salt (2% NaCl) diet. Mean arterial pressure (MAP) was measured by radio telemetry during 3 control days, 10‐days of AngII infusion (10 ng/kg/min, iv), and a 3‐day recovery period. MAP was not different between groups during the 3 day control period. However, by day 7 of AngII, MAP was higher in sham (158 ± 3 mmHg) compared to OVLTx rats (147 ± 3 mmHg) and remained higher throughout AngII infusion. MAP returned to control levels in both groups during the recovery period. These results suggest that the OVLT contributes to AngII‐salt hypertension in the rat. Supported by HL076312.