Effects of chronic lesions of the anteroventral third ventricle region on baroreceptor reflex function in conscious rats

This study determined baroreceptor reflex (BR) function in conscious rats w hich had received sham or electrolytic lesions of the anteroventral third v entricle (AV3V) 54-56 days previously. Resting mean arterial pressure (MAP) and heart rate (HR) values of the AV3V-lesion rats were similar to those o f sham-lesion rats (P > 0.05 for both comparisons). The sensitivity of the BR-mediated tachycardia in AV3V-lesion was greater than in sham-lesion rats (-9.92 +/- 1.00 vs. -4.54 +/- 0.45 bpm/mmHg. P < 0.05), The sensitivity of the BR-mediated bradycardia in AV3V-lesion rats was also greater than in r ats with sham lesions (-3.56 +/- 0.38 vs. -2.06 +/- 0.42 bpm/mmHg, P < 0.05 ). The AV3V lesions did not affect other BR parameters. These findings demo nstrate that chronic lesions of the AV3V region increase the sensitivity of the baroreceptor HR reflex in conscious rats. (C) 1999 Published by Elsevi er Science B.V. All rights reserved.