Document Detail

Dynamic time-varying analysis of heart rate and blood pressure variability in cats exposed to short-term chronic intermittent hypoxia.
MedLine Citation:
PMID:  18463194     Owner:  NLM     Status:  MEDLINE    
Chronic intermittent hypoxia (CIH) contributes to the development of hypertension in patients with obstructive sleep apnea and animal models. However, the early cardiovascular changes that precede CIH-induced hypertension are not completely understood. Nevertheless, it has been proposed that one of the possible contributing mechanisms to CIH-induced hypertension is a potentiation of carotid body (CB) hypoxic chemoreflexes. Therefore, we studied the dynamic responses of heart rate, blood pressure, and their variabilities during acute exposure to different levels of hypoxia after CIH short-term preconditioning (4 days) in cats. In addition, we measured baroreflex sensitivity (BRS) on the control of heart rate by noninvasive techniques. To assess the relationships among these indexes and CB chemoreflexes, we also recorded CB chemosensory discharges. Our data show that short-term CIH reduced BRS, potentiated the increase in heart rate induced by acute hypoxia, and was associated with a dynamic shift of heart rate variability (HRV) spectral indexes toward the low-frequency band. In addition, we found a striking linear correlation (r = 0.97) between the low-to-high frequency ratio of HRV and baseline. CB chemosensory discharges in the CIH-treated cats. Thus, our results suggest that cyclic hypoxic stimulation of the CB by short-term CIH induces subtle but clear selective alterations of HRV and BRS in normotensive cats.
Sergio Rey; Mika P Tarvainen; Pasi A Karjalainen; Rodrigo Iturriaga
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-05-07
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  295     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2008 Jul 
Date Detail:
Created Date:  2008-07-10     Completed Date:  2008-09-03     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R28-37     Citation Subset:  IM    
Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
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MeSH Terms
Anoxia / physiopathology*
Baroreflex / physiology
Blood Pressure / physiology*
Chronic Disease
Heart Rate / physiology*
Time Factors

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