Enhanced activity of central adrenergic neurons in two-kidney, one clip hypertension in Sprague-Dawley rats

The present study was aimed at investigating whether two-kidney, one clip (2K1C) hypertension is associated with an enhanced central adrenergic activity. Rats were made 2K1C hypertensive, and the expression of Fos-like immunoreactivity (FLI) and phenylethanalamine N-methyltransferase (PNMT)-immunoreactivity was determined in the brain areas related to the cardiovascular regulation. In 2K1C hypertension, the basal Fos-immunoreactivity was significantly increased in rostral ventrolateral medulla (RVLM), paraventricular nucleus (PVN), and supraoptic nucleus (SON). PNMT-immunoreactivities were noted in RVLM, but not in PVN or SON. Intracerebroventricular administration of angiotensin 11 (All) markedly increased Fos-immunoreactivities, the degree of which was greater in hypertension. Furthermore, All increased the ratio of PNMT-positive/Fos-positive neurons in RVLM in hypertension. It is suggested that the responsiveness to All of the central adrenergic system is enhanced in 2K1C hypertension. (C) 2004 Elsevier Ireland Ltd. All rights reserved.