C-type natriuretic peptide expression in olfactory regions of rat brain ismodulated by acute water deprivation, salt loading and central angiotensinII

To elucidate the central role of c-type natriuretic peptide (CNP), levels o f CNP mRNA in control rat brain were compared with levels following acute w ater deprivation, salt loading and central administration of angiotensin II (AII), using Northern blot and in situ hybridisation. Rats with water depr ivation (WD) had no access to water for 48 h, rats with salt loading (SL) h ad 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 S L, In the medulla, WD and SL both increased CNP mRNA, but levels of CNP mRN A elsewhere in the brain were not significantly altered, Intracerebroventri cular All (500 ng) increased water intake, and induced a significant increa se in CNP expression at 4 h in olfactory regions, but not in other brain si tes. In summary, CNP expression is regulated in olfactory regions of the ra t brain in response to acute challenges to water and salt balance and by ce ntral All. Copyright (C) 2001 S. Karger AG, Basel.