AJP - Regulatory, Integrative and Comparative Physiology, Vol 261, Issue 3 647-R651, Copyright © 1991 by American Physiological Society
Hypothalamic lesions increase saline ingestion induced by injection of angiotensin II into AV3V in rats
L. A. Camargo, W. A. Saad, A. Renzi, L. A. de Luca Junior, J. R. Goncalves and J. V. Menani
Department of Physiology, School of Dentistry, Paulista State University, Araraquara, SP, Brazil.
Water and 3% NaCl intake were increased by the injection of 4 ng
angiotensin II (ANG II) into the anteroventral third ventricle (AV3V)
region of rats. Pretreatment with two specific ANG II receptor antagonists,
[octanoyl-Leu8]ANG II and [Leu8]ANG II, significantly reduced ANG
II-induced water and saline intake. This inhibition lasted approximately 30
min, with partial recovery at 60 min. In rats with electrolytic lesion of
the bilateral ventromedial nucleus of hypothalamus (VMH), the effect of ANG
II on water intake was not different from that observed in sham rats, but
saline ingestion increased. In summary, the present results show that the
AV3V region is an important central structure for ANG II-induced saline
ingestion. Lesion of the VMH increases the response to ANG II, showing an
interaction between the AV3V region and the VMH in the regulation of salt
ingestion.
