|
|
||||||||
1 First Department of Internal Medicine, Nagoya University School of Medicine, Nagoya 466-8550; and 2 Third Department of Internal Medicine, Nagoya City University Medical School, Nagoya 467-8601, Japan
To examine whether the impacts of hypoxia on
autonomic regulations involve the phasic modulations as well as tonic
controls of cardiovascular variables, heart rate, blood pressure, and
their variability during isocapnic progressive hypoxia were analyzed in
trained conscious dogs prepared with a permanent tracheostomy and an
implanted blood pressure telemetry unit. Data were obtained at baseline
and when minute ventilation (
I) first reached 10 (
I10), 15 (
I15), and 20 (
I20) l/min during hypoxia. Time-dependent changes
in the amplitudes of the high-frequency component of the R-R interval
(RRIHF) and the low-frequency component of mean arterial pressure
(MAPLF) were analyzed by complex demodulation. In a total of 47 progressive hypoxic runs in three dogs, RRIHF decreased at
I15 and
I20 and MAPLF increased
at
I10 and
I15 but not at
I20, whereas heart rate and arterial pressure
increased progressively with advancing hypoxia. We conclude that the
autonomic responses to isocapnic progressive hypoxia involve tonic
controls and phasic modulations of cardiovascular variables; the latter may be characterized by a progressive reduction in respiratory vagal
modulation of heart rate and a transient augmentation in low-frequency
sympathetic modulation of blood pressure.
sympathetic nervous system; parasympathetic nervous system; trained dog; complex demodulation; respiratory sinus arrhythmia; Mayer waves
This article has been cited by other articles:
![]() |
Y. C. Tzeng, P. D. Larsen, and D. C. Galletly Effects of hypercapnia and hypoxemia on respiratory sinus arrhythmia in conscious humans during spontaneous respiration Am J Physiol Heart Circ Physiol, May 1, 2007; 292(5): H2397 - H2407. [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] |
||||
![]() |
G. E. Foster, D. C. McKenzie, W. K. Milsom, and A. W. Sheel Effects of two protocols of intermittent hypoxia on human ventilatory, cardiovascular and cerebral responses to hypoxia J. Physiol., September 1, 2005; 567(2): 689 - 699. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Vaschillo, B. Vaschillo, P. Lehrer, F. Yasuma, and J.-i. Hayano Heartbeat Synchronizes With Respiratory Rhythm Only Under Specific Circumstances Chest, October 1, 2004; 126(4): 1385 - 1387. [Full Text] [PDF] |
||||
![]() |
N. D. Giardino, R. W. Glenny, S. Borson, and L. Chan Respiratory sinus arrhythmia is associated with efficiency of pulmonary gas exchange in healthy humans Am J Physiol Heart Circ Physiol, May 1, 2003; 284(5): H1585 - H1591. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |