| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
Submitted 10 September 2004 ; accepted in final form 5 January 2005
Chronic heart failure is often associated with sympathoexcitation and blunted arterial baroreflex function. These phenomena have been causally linked to elevated central ANG II mechanisms. Recent studies have shown that NAD(P)H oxidase-derived reactive oxygen species (ROS) are important mediators of ANG II signaling and therefore might play an essential role in these interactions. The aims of this study were to determine whether central subchronic infusion of ANG II in normal animals has effects on O2– production and expression of NAD(P)H oxidase subunits as well as ANG II type 1 (AT1) receptors in the rostral ventrolateral medulla (RVLM). Twenty-four male New Zealand White rabbits were divided into four groups and separately received a subchronic intracerebroventricular infusion of saline alone, ANG II alone, ANG II with losartan, and losartan alone for 1 wk. On day 7 of intracerebroventricular infusion, mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA) values were recorded, and arterial baroreflex sensitivity was evaluated while animals were in the conscious state. We found that ANG II significantly increased baseline RSNA (161.9%; P < 0.05), mRNA and protein expression of AT1 receptors (mRNA, 66.7%; P < 0.05; protein, 85.1%; P < 0.05), NAD(P)H oxidase subunits (mRNA, 120.0–200.0%; P < 0.05; protein, 90.9–197.0%; P < 0.05), and O2– production (83.2%; P < 0.05) in the RVLM. In addition, impaired baroreflex control of HR (Gainmax reduced by 48.2%; P < 0.05) and RSNA (Gainmax reduced by 53.6%; P < 0.05) by ANG II was completely abolished by losartan. Losartan significantly decreased baseline RSNA (–49.5%; P < 0.05) and increased baroreflex control of HR (Gainmax increased by 64.8%; P < 0.05) and RSNA (Gainmax increased by 67.9%; P < 0.05), but had no significant effects on mRNA and protein expression of AT1 receptor and NAD(P)H oxidase subunits and O2– production in the RVLM. These data suggest that in normal rabbits, NAD(P)H oxidase-derived ROS play an important role in the modulation of sympathetic activity and arterial baroreflex function by subchronic central treatment of exogenous ANG II via AT1 receptors.
baroreflex; renal sympathetic nerve activity; free radicals; angiotensin II type 1 receptor; rostral ventrolateral medulla; reactive oxygen species
This article has been cited by other articles:
|
|
 |
|
  G. R. Borges, H. C. Salgado, C. A. A. Silva, M. A. Rossi, C. M. Prado, and R. Fazan Jr. Changes in hemodynamic and neurohumoral control cause cardiac damage in one-kidney, one-clip hypertensive mice Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2008; 295(6): R1904 - R1913. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Lazartigues, P. Sinnayah, G. Augoyard, C. Gharib, A. K. Johnson, and R. L. Davisson Enhanced water and salt intake in transgenic mice with brain-restricted overexpression of angiotensin (AT1) receptors Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2008; 295(5): R1539 - R1545. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Wang, T. A. Milner, R. C. Speth, A. C. Gore, D. Wu, C. Iadecola, and J. P. Pierce Sex differences in angiotensin signaling in bulbospinal neurons in the rat rostral ventrolateral medulla Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2008; 295(4): R1149 - R1157. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. Bagi, N. Erdei, and A. Koller High intraluminal pressure via H2O2 upregulates arteriolar constrictions to angiotensin II by increasing the functional availability of AT1 receptors Am J Physiol Heart Circ Physiol, August 1, 2008; 295(2): H835 - H841. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Liu, L. Gao, S. K. Roy, K. G. Cornish, and I. H. Zucker Role of Oxidant Stress on AT1 Receptor Expression in Neurons of Rabbits With Heart Failure and in Cultured Neurons Circ. Res., July 18, 2008; 103(2): 186 - 193. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Gao, W. Wang, and I. H. Zucker Simvastatin Inhibits Central Sympathetic Outflow in Heart Failure by a Nitric-Oxide Synthase Mechanism J. Pharmacol. Exp. Ther., July 1, 2008; 326(1): 278 - 285. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. H. Zucker Angiotensin-Converting Enzyme 2: A New Player in Central Sympathetic Regulation? Circ. Res., March 28, 2008; 102(6): 628 - 629. [Full Text] [PDF]
|
|
|
|
 |
|
 T. M. Mousa, D. Liu, K. G. Cornish, and I. H. Zucker Exercise training enhances baroreflex sensitivity by an angiotensin II-dependent mechanism in chronic heart failure J Appl Physiol, March 1, 2008; 104(3): 616 - 624. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Yu, S.-G. Wei, Z.-H. Zhang, E. Gomez-Sanchez, R. M. Weiss, and R. B. Felder Does Aldosterone Upregulate the Brain Renin-Angiotensin System in Rats With Heart Failure? Hypertension, March 1, 2008; 51(3): 727 - 733. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Kawada, T. Yamazaki, T. Akiyama, M. Li, C. Zheng, T. Shishido, H. Mori, and M. Sugimachi Angiotensin II attenuates myocardial interstitial acetylcholine release in response to vagal stimulation Am J Physiol Heart Circ Physiol, October 1, 2007; 293(4): H2516 - H2522. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Gao, W. Wang, D. Liu, and I. H. Zucker Exercise Training Normalizes Sympathetic Outflow by Central Antioxidant Mechanisms in Rabbits With Pacing-Induced Chronic Heart Failure Circulation, June 19, 2007; 115(24): 3095 - 3102. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Q. Chen and H.-L. Pan Signaling Mechanisms of Angiotensin II-Induced Attenuation of GABAergic Input to Hypothalamic Presympathetic Neurons J Neurophysiol, May 1, 2007; 97(5): 3279 - 3287. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. N. Mayorov Brain superoxide as a key regulator of the cardiovascular response to emotional stress in rabbits Exp Physiol, May 1, 2007; 92(3): 471 - 479. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y.-X. Pan, L. Gao, W.-Z. Wang, H. Zheng, D. Liu, K. P. Patel, I. H. Zucker, and W. Wang Exercise Training Prevents Arterial Baroreflex Dysfunction in Rats Treated With Central Angiotensin II Hypertension, March 1, 2007; 49(3): 519 - 527. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. H. Zucker Novel Mechanisms of Sympathetic Regulation in Chronic Heart Failure Hypertension, December 1, 2006; 48(6): 1005 - 1011. [Full Text] [PDF]
|
|
|
|
|
|
D. Liu, L. Gao, S. K. Roy, K. G. Cornish, and I. H. Zucker Neuronal Angiotensin II Type 1 Receptor Upregulation in Heart Failure: Activation of Activator Protein 1 and Jun N-Terminal Kinase Circ. Res., October 27, 2006; 99(9): 1004 - 1011. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Ye, H. Zhong, and V. M. Campese Oxidative Stress Mediates the Stimulation of Sympathetic Nerve Activity in the Phenol Renal Injury Model of Hypertension Hypertension, August 1, 2006; 48(2): 309 - 315. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. H. Zucker and L. Gao The Regulation of Sympathetic Nerve Activity by Angiotensin II Involves Reactive Oxygen Species and MAPK Circ. Res., October 14, 2005; 97(8): 737 - 739. [Full Text] [PDF]
|
|
|
|
|
|
L. Gao, W. Wang, Y.-L. Li, H. D. Schultz, D. Liu, K. G. Cornish, and I. H. Zucker Simvastatin Therapy Normalizes Sympathetic Neural Control in Experimental Heart Failure: Roles of Angiotensin II Type 1 Receptors and NAD(P)H Oxidase Circulation, September 20, 2005; 112(12): 1763 - 1770. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
