| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Hypertension Unit, University of Ottawa Heart Institute, Ottawa, Canada
2 Medicine, Duke University Medical Center, Durham, North Carolina, United States
* To whom correspondence should be addressed. E-mail: fleenen{at}ottawaheart.ca.
Functional studies indicate that the sympatho-excitatory and pressor responses
to an increase in CSF [Na+] by central infusion of Na+-rich artificial cerebrospinal fluid (aCSF) in Wistar rats are mediated in the brain by mineralocorticoid receptor (MR) activation, ouabain-like compounds (OLC) and AT1-receptor stimulation. In the present
study, we examined whether increasing CSF [Na+] by icv infusion of Na+-rich aCSF activates MR and thereby increases OLC and components of the renin-angiotensin system in the brain. Male Wistar rats received via osmotic minipump an icv infusion of aCSF or Na+-rich aCSF, in some groups combined with icv infusion of spironolactone (100 ng/hr), antibody Fab fragments (to bind OLC) or as control 
-globulins. After 2 wks of infusion, resting BP and HR were recorded, OLC and aldosterone content in the hypothalamus were assessed by a specific ELISA or radio-immunoassay, and angiotensin-converting enzyme (ACE) and AT1-receptor binding densities in various brain nuclei measured by autoradiography using 125I-labelled 351 A and 125I-labelled Ang II. Compared to icv aCSF, icv Na+-rich aCSF increased CSF [Na+] by ~5 mmol/L, MAP by ~20 mmHg, HR by ~65 bpm, and hypothalamic content of OLC by 50% and of aldosterone by 33%. Icv spironolactone did not affect CSF [Na+], but blocked the Na+-
rich aCSF induced increases in BP and HR and OLC content. Icv Na+-rich aCSF increased ACE and AT1-receptor binding densities in several brain nuclei, and Fab fragments blocked these increases. These data indicate that in Wistar rats, a chronic
increase in CSF [Na+] may increase hypothalamic aldosterone and activates CNS pathways involving MR, and OLC, leading to increases in AT1-receptor and ACE densities in brain areas involved in cardiovascular regulation and hypertension.
This article has been cited by other articles:
|
|
 |
|
  X. Hou, S. F. Theriault, I. Dostanic-Larson, A. E. Moseley, J. B Lingrel, H. Wu, S. Dean, and J. W. Van Huysse Enhanced pressor response to increased CSF sodium concentration and to central ANG I in heterozygous {alpha}2 Na+-K+-ATPase knockout mice Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2009; 296(5): R1427 - R1438. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. S. Huang, R. A. White, A. Y. Jeng, and F. H. H. Leenen Role of central nervous system aldosterone synthase and mineralocorticoid receptors in salt-induced hypertension in Dahl salt-sensitive rats Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2009; 296(4): R994 - R1000. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Gabor and F. H. H. Leenen Mechanisms in the PVN mediating local and central sodium-induced hypertension in Wistar rats Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2009; 296(3): R618 - R630. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. S. Huang, R. A. White, M. Ahmad, A. Y. Jeng, and F. H. H. Leenen Central infusion of aldosterone synthase inhibitor prevents sympathetic hyperactivity and hypertension by central Na+ in Wistar rats Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2008; 295(1): R166 - R172. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z.-H. Zhang, Y. Yu, Y.-M. Kang, S.-G. Wei, and R. B. Felder Aldosterone acts centrally to increase brain renin-angiotensin system activity and oxidative stress in normal rats Am J Physiol Heart Circ Physiol, February 1, 2008; 294(2): H1067 - H1074. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. N. Orlov and A. A. Mongin Salt-sensing mechanisms in blood pressure regulation and hypertension Am J Physiol Heart Circ Physiol, October 1, 2007; 293(4): H2039 - H2053. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Schoner and G. Scheiner-Bobis Endogenous and exogenous cardiac glycosides: their roles in hypertension, salt metabolism, and cell growth Am J Physiol Cell Physiol, August 1, 2007; 293(2): C509 - C536. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. B. Eap, M. Bochud, R. C. Elston, P. Bovet, M. P. Maillard, J. Nussberger, L. Schild, C. Shamlaye, and M. Burnier CYP3A5 and ABCB1 Genes Influence Blood Pressure and Response to Treatment, and Their Effect Is Modified by Salt Hypertension, May 1, 2007; 49(5): 1007 - 1014. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
