AJP - Regulatory, Integrative and Comparative Physiology, Vol 267, Issue 3 792-R798, Copyright © 1994 by American Physiological Society
Comparison of fos-like immunoreactivity induced in rat brain by central injection of angiotensin II and carbachol
N. E. Rowland, B. H. Li, A. K. Rozelle and G. C. Smith
Department of Psychology, University of Florida, Gainesville 32611-2065.
Rats were given intracerebroventricular injections of either angiotensin II
(ANG II) or the cholinomimetic carbachol. Some rats received cotreatment
with ANG II antagonists selective for either angiotensin receptor AT1
(losartan) or AT2 (PD-123319, CGP-42112A). One hour later, the rats were
killed and the brains processed for immunocytochemical detection of
Fos-like immunoreactivity (FLI). ANG II treatment induced strong FLI in the
anterior subfornical organ (SFO), median preoptic nucleus (MnPO), organum
vasculosum laminae terminalis (OVLT), and supraoptic and paraventricular
hypothalamic nuclei (SON, PVH). The AT1 antagonist abolished FLI in all
regions normally stimulated by ANG II. The AT2 antagonist PD-123319 reduced
FLI in SON and PVH, but CGP-42112A was less effective. Carbachol induced
strong FLI in SON, PVH, and MnPO and only moderate FLI in SFO and OVLT. The
AT1 antagonist prevented carbachol-induced FLI in the MnPO only. The
distributions of FLI are compared between these central dipsogens and with
that previously reported after peripheral infusion of ANG II, and their
implications for mapping central thirst pathways are discussed.
