AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 6 1401-R1405, Copyright © 1995 by American Physiological Society
Angiotensin II-induced thirst, but not sodium appetite, via AT1 receptors in organum cavum prelamina terminalis
M. el Ghissassi, S. N. Thornton and S. Nicolaidis
Laboratoire de Neurobiologie des Regulations, Centre National de la Recherche Scientifique, College de France, Paris.
The angiotensin receptor specificity, with respect to fluid intake, of the
organum cavum prelamina terminalis (OCPLT), a recently discovered discrete
forebrain structure with high sensitivity to angiotensin II (ANG II), was
investigated. ANG II (10 ng) microinjected into the OCPLT significantly
increased water consumption but did not induce intake of a hypertonic (3%)
NaCl solution. Losartan, an ANG II type 1 (AT1) receptor-specific
antagonist, produced dose-related (1-100 ng) inhibition of ANG II-induced
drinking. The ANG II type 2 receptor-specific antagonist CGP-42112A was
ineffective. Intake of the 3% NaCl solution in response to microinjection
of either of the antagonists into the OCPLT was never observed. These
findings suggest that water intake produced by microinjection of ANG II
into the OCPLT is mediated by AT1 receptors uniquely and that, in contrast
to other regions of the brain, these receptors do not induce salt intake
when stimulated by ANG II.
