Lesion of the anteroventral third ventricle region abolishes the beneficial effects of hypertonic saline on hemorrhagic shock in rats

Abstract

The effect of intravenous infusion of hypertonic saline (HS, 7.5% NaCl) on the recovery of mean arterial pressure (MAP) during hemorrhage was studied in sham-operated rats and in rats with electrolytic lesion in the anteroventral third ventricle (AV3V) region. After intravenous infusion of 7.5% NaCl (4 ml/kg b.wt.), MAP increased from about 60 to 90 mmHg in sham rats and became stable at this level during all the time of observation (30 min). In AV3V-lesioned rats, after the same infusion, the MAP increased to 80 mmHg, but returned to the pre-infusion levels within 30 min. These results show that the integrity of the AV3V region is important for the beneficial effect of HS during hemorrhagic shock in rats. The AV3V lesion disrupts neural pathways involved in the maintenance of fluid balance and these changes probably abolish the effect of hypertonic saline.