AJP - Regu Ad Instruments
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Regul Integr Comp Physiol 295: R741-R750, 2008. First published July 2, 2008; doi:10.1152/ajpregu.00157.2008
0363-6119/08 $8.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
295/3/R741    most recent
00157.2008v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Maliszewska-Scislo, M.
Right arrow Articles by Rossi, N. F.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Maliszewska-Scislo, M.
Right arrow Articles by Rossi, N. F.

CALL FOR PAPERS
Physiological and Molecular Mechanisms Implicated in the Neural Control of Circulation

Subfornical organ differentially modulates baroreflex function in normotensive and two-kidney, one-clip hypertensive rats

Maria Maliszewska-Scislo,1 Haiping Chen,1 Robert A. Augustyniak,1,2 Dale Seth,3 and Noreen F. Rossi1,2

Departments of 1Internal Medicine and 2Physiology, Wayne State University School of Medicine and John D. Dingell Veterans Administration Medical Center, Detroit, Michigan; and 3Department of Physiology and the Renal and Hypertension Center, Tulane University, New Orleans, Louisiana

Submitted 1 March 2008 ; accepted in final form 23 June 2008

During activation of the renin-angiotensin system, hindbrain circumventricular organs such as the area postrema have been implicated in modulating the arterial baroreflex. This study was undertaken to test the hypothesis that the subfornical organ (SFO), a forebrain circumventricular structure, may also modulate the baroreflex. Studies were performed in rats with two-kidney, one-clip (2K,1C) hypertension as a model of endogenously activated renin-angiotensin system. Baroreflex function was ascertained during ramp infusions of phenylephrine and nitroprusside in conscious sham-clipped and 5-wk 2K,1C rats with either a sham or electrolytically lesioned SFO. Lesioning significantly decreased mean arterial pressure in 2K,1C rats from 158 ± 7 to 131 ± 4 mmHg but not in sham-clipped rats. SFO-lesioned, sham-clipped rats had a significantly higher upper plateau and range of the renal sympathetic nerve activity-mean arterial pressure relationship compared with sham-clipped rats with SFO ablation. In contrast, lesioning the SFO in 2K,1C rats significantly decreased both the upper plateau and range of the baroreflex control of renal sympathetic nerve activity, but only the range of the baroreflex response of heart rate decreased. Thus, during unloading of the baroreceptors, the SFO differentially modulates the baroreflex responses in sham-clipped vs. 2K,1C rats. Since lesioning the SFO did not influence plasma angiotensin II (ANG II), the effects of the SFO lesion are not caused by changes in circulating levels of ANG II. These findings support a pivotal role for the SFO in the sympathoexcitation observed in renovascular hypertension and in baroreflex regulation of sympathetic activity in both normal and hypertensive states.

Goldblatt kidney; renal sympathetic nerve activity; angiotensin II; vasopressin


Address for reprint requests and other correspondence: N. F. Rossi, Depts. of Internal Medicine and Physiology, Wayne State Univ. School of Medicine, 4160 John R. St., #908, Detroit, MI 48201 (e-mail: nrossi{at}med.wayne.edu)






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2008 by the American Physiological Society.