| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1Institute of Neuroscience and 2Department of Physiology, Tzu-Chi University, Hualien; and 3Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
Submitted 29 August 2005 ; accepted in final form 13 February 2006
Long-term exposure to intermittent hypoxia (IH), such as that occurring in association with sleep apnea, may result in systemic hypertension; however, the time course changes in arterial pressure, autonomic functions, and baroreflex sensitivity are still unclear. We investigated the changes in cardiovascular neural regulations during the development of chronic IH-induced hypertension in rats. Sprague-Dawley rats were exposed to repetitive 1.25-min cycles (30 s of N2 + 45 s of 21% O2) of IH or room air (RA) for 6 h/day during light phase (10 AM-4 PM) for 30 days. Arterial pressure was measured daily using the telemetry system during RA breathing. The mean arterial pressure (MAP) and interpulse interval (PPI) signals were then used to assess the autonomic functions and spontaneous baroreflex sensitivity by auto- and cross-spectral analysis, respectively. Stable MAP, low-frequency power of MAP (BLF), and low-frequency power (LF)-to-high frequency power (HF) ratio of PPI (LF/HF) were significantly higher in IH-exposed rats, compared with those of RA-exposed rats. Elevation of the MAP, BLF, LF/HF, and minute ventilation started 5 days after IH exposure and lasted until the end of the 30-day observation period. Additionally, IH-exposed rats had significant lower slope of MAP-PPI linear regression (under a successively descending and ascending) and magnitude of MAP-PPI transfer function (at frequency ranges of 0.06–0.6 Hz or 0.6–2.4 Hz) after IH exposure for 17 days. However, RA-exposed rats did not exhibit these changes. The results of this study indicate that chronic IH-induced hypertension is associated with a facilitation of cardiovascular sympathetic outflow and inhibition of baroreflex sensitivity in conscious rats.
autonomic functions; spontaneous baroreflex sensitivity; peripheral chemoreflex sensitivity
This article has been cited by other articles:
|
|
 |
|
  S Ryan, C T Taylor, and W T McNicholas Systemic inflammation: a key factor in the pathogenesis of cardiovascular complications in obstructive sleep apnoea syndrome? Thorax, July 1, 2009; 64(7): 631 - 636. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Yan, L. Li, S. W. Harden, D. Gozal, Y. Lin, W. B. Wead, R. D. Wurster, and Z. Cheng Chronic intermittent hypoxia impairs heart rate responses to AMPA and NMDA and induces loss of glutamate receptor neurons in nucleus ambiguus of F344 rats Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2009; 296(2): R299 - R308. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Rey, M. P. Tarvainen, P. A. Karjalainen, and R. Iturriaga Dynamic time-varying analysis of heart rate and blood pressure variability in cats exposed to short-term chronic intermittent hypoxia Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2008; 295(1): R28 - R37. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Yokoe, L. C. Alonso, L. C. Romano, T. C. Rosa, Robert. M. O'Doherty, A. Garcia-Ocana, K. Minoguchi, and C. P. O'Donnell Intermittent hypoxia reverses the diurnal glucose rhythm and causes pancreatic {beta}-cell replication in mice J. Physiol., February 1, 2008; 586(3): 899 - 911. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Gu, M. Lin, J. Liu, D. Gozal, K. E. Scrogin, R. Wurster, M. W. Chapleau, X. Ma, and Z. Cheng Selective impairment of central mediation of baroreflex in anesthetized young adult Fischer 344 rats after chronic intermittent hypoxia Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H2809 - H2818. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Lin, R. Liu, D. Gozal, W. B. Wead, M. W. Chapleau, R. Wurster, and Z. Cheng Chronic intermittent hypoxia impairs baroreflex control of heart rate but enhances heart rate responses to vagal efferent stimulation in anesthetized mice Am J Physiol Heart Circ Physiol, August 1, 2007; 293(2): H997 - H1006. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. Patruno, S. Aiolfi, G. Costantino, R. Murgia, C. Selmi, A. Malliani, and N. Montano Fixed and Autoadjusting Continuous Positive Airway Pressure Treatments Are Not Similar in Reducing Cardiovascular Risk Factors in Patients With Obstructive Sleep Apnea Chest, May 1, 2007; 131(5): 1393 - 1399. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Ryan, S. Ward, C. Heneghan, and W. T. McNicholas Predictors of Decreased Spontaneous Baroreflex Sensitivity in Obstructive Sleep Apnea Syndrome Chest, April 1, 2007; 131(4): 1100 - 1107. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. B. Zoccal, L. G. H. Bonagamba, F. R. T. Oliveira, J. Antunes-Rodrigues, and B. H. Machado Increased sympathetic activity in rats submitted to chronic intermittent hypoxia Exp Physiol, January 1, 2007; 92(1): 79 - 85. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. E. Foster, M. J. Poulin, and P. J. Hanly Sleep Apnoea & Hypertension: Physiological bases for a causal relation: Intermittent hypoxia and vascular function: implications for obstructive sleep apnoea Exp Physiol, January 1, 2007; 92(1): 51 - 65. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Rondon, M. S. Brasileiro-Santos, E. D. Moreira, M. U. P. B. Rondon, K. C. Mattos, M. A. Coelho, G. J. J. Silva, P. C. Brum, P. Fiorino, M. C. Irigoyen, et al. Exercise training improves aortic depressor nerve sensitivity in rats with ischemia-induced heart failure Am J Physiol Heart Circ Physiol, December 1, 2006; 291(6): H2801 - H2806. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
