Regional suppression by water intake of c-fos expression induced by intraventricular infusions of angiotensin II.
Intracerebroventricular (i.c.v.) infusions of angiotensin II (AII) reliably induced c-fos expression in the supraoptic (SON) and paraventricular (PVN) nuclei, as well as other areas of the basal forebrain including the OVLT, subfornical organ (SFO), and bed nucleus (BNST). Double-labelling showed that AII-induced c-fos was observed in both vasopressin (AVP-) and oxytocin (OXY)-containing neurons of the SON and PVN in male rats. Allowing rats to drink water after AII infusions suppressed c-fos expression both AVP- and OXY-stained magnocellular neurons. Intragastric infusions of water were also effective, showing that oro-pharyngeal stimuli were not critical. Maximal suppression occurred in rats in whom water had been infused intragastrically about 5 min before i.c.v. AII infusions, suggesting that changes in osmolarity were responsible. i.c.v. AII also induced c-fos expression in a number of brainstem structures, including the solitary nucleus (NTS), lateral parabrachial nucleus (LPBN), locus coeruleus (LC), and the area postrema (AP). These results indicate that AVP and OXY-containing neurons in the magnocellular parts of the SON and PVN alter their immediate-early gene response to AII after water intake, and that this does not depend upon oro-pharyngeal factors. Furthermore, AII can induce c-fos expression in a number of brainstem nuclei associated with autonomic function, and these do not respond to water intake.
Xu
Z
Z
Department of Anatomy, University of Cambridge, UK.
Herbert
J
J
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism; D001769:Blood / Q000378:metabolism; D001921:Brain / Q000166:cytology / Q000502:physiology*; D001933:Brain Stem / Q000378:metabolism; D004326:Drinking / Q000502:physiology*; D007276:Injections, Intraventricular; D008297:Male; D009474:Neurons / Q000378:metabolism; D009994:Osmolar Concentration; D010121:Oxytocin / Q000378:metabolism; D016548:Prosencephalon / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
D016760:Proto-Oncogene Proteins c-fos; D000804:Angiotensin II; D001127:Arginine Vasopressin; D010121:Oxytocin