title: C-type natriuretic peptide expression in olfactory regions of rat brain is modulated by acute water deprivation, salt loading and central angiotensin II.
abstract: To elucidate the central role of c-type natriuretic peptide (CNP), levels of CNP mRNA in control rat brain were compared with levels following acute water deprivation, salt loading and central administration of angiotensin II (AII), using Northern blot and in situ hybridisation. Rats with water deprivation (WD) had no access to water for 48 h, rats with salt loading (SL) had access to 2% saline for 48 h, and control rats had free access to water. Both WD and SL significantly raised plasma sodium (Na). Levels of CNP mRNA in olfactory regions were significantly decreased in WD and increased in SL. In the medulla, WD and SL both increased CNP mRNA, but levels of CNP mRNA elsewhere in the brain were not significantly altered. Intracerebroventricular AII (500 ng) increased water intake, and induced a significant increase in CNP expression at 4 h in olfactory regions, but not in other brain sites. In summary, CNP expression is regulated in olfactory regions of the rat brain in response to acute challenges to water and salt balance and by central AII.
authors.affiliation: Christchurch Cardioendocrine Research Group, Christchurch School of Medicine, Christchurch, New Zealand. vicky.cameron@chmeds.ac.nz
authors.forename: V A
authors.initials: VA
authors.lastname: Cameron
authors.forename: S A
authors.initials: SA
authors.lastname: Cumming
authors.forename: E A
authors.initials: EA
authors.lastname: Espiner
authors.forename: G
authors.initials: G
authors.lastname: Nicholls
authors.forename: M
authors.initials: M
authors.lastname: Richards
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D015152:Blotting, Northern; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D007032:Hypothalamus, Anterior / Q000502:physiology; D017403:In Situ Hybridization; D007276:Injections, Intraventricular; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology; D020098:Natriuretic Peptide, C-Type / Q000235:genetics*; D009830:Olfactory Bulb / Q000502:physiology*; D011149:Pons / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride / Q000494:pharmacology*; D014868:Water Deprivation / Q000502:physiology*; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology
chemical_list: D012333:RNA, Messenger; D000804:Angiotensin II; D020098:Natriuretic Peptide, C-Type; D012965:Sodium Chloride