|
|
||||||||
Journal of Applied Physiology, Vol 67, Issue 2 578-583, Copyright © 1989 by American Physiological Society
ARTICLES |
M. Bonora and H. Gautier
Laboratoire de Physiologie Respiratoire, Faculte de Medecine Saint-Antoine, Paris, France.
The effects of the level of oxygenation on the respiratory response to heat exposure have been studied in conscious cats during normoxia, severe or mild hypocapnic hypoxia [inspired O2 fraction (FIO2) = 0.11 or 0.13], or hyperoxia. Several cats were also studied during severe normocapnic hypoxia. Experiments were repeated while the same animals were chronically carotid body denervated (CBD). The increase in respiratory frequency (f) leading to thermal tachypnea occurred at a lower body temperature (Tb) in severe hypocapnic hypoxia than in ambient air, but this effect was less pronounced when hypocapnia was corrected. No significant changes were observed during mild hypoxia or hyperoxia compared with normoxia in intact animals. After CBD, thermal tachypnea occurred at lower Tb in air than it did with intact animals in three of five cats, and it also occurred at lower Tb in mild hypocapnic hypoxia compared with air. It appears, therefore, that in conscious cats exposed to heat load 1) severe hypoxia enhances thermal tachypnea, 2) this effect persists after CBD, which suggests that it originates from a central action of hypoxia, and 3) the chemoreceptor afferents, to some degree, inhibit the onset of thermal tachypnea, as was previously observed for hypoxic tachypnea, which appears only in CBD cats (J. Appl. Physiol. 49: 769-777, 1980). Therefore, triggering of thermal and hypoxic tachypnea may involve common central mechanisms, probably located in the diencephalic structures under the control of afferents from arterial chemoreceptors.
This article has been cited by other articles:
![]() |
M. Cabanac Adjustable set point: to honor Harold T. Hammel J Appl Physiol, April 1, 2006; 100(4): 1338 - 1346. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. A. Romanovsky Do fever and anapyrexia exist? Analysis of set point-based definitions Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2004; 287(4): R992 - R995. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. A. Steiner, E. C. Carnio, and L. G. S. Branco Role of neuronal nitric oxide synthase in hypoxia-induced anapyrexia in rats J Appl Physiol, September 1, 2000; 89(3): 1131 - 1136. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Gautier Invited Editorial on "Oxygen transport in conscious newborn dogs during hypoxic hypometabolism" J Appl Physiol, March 1, 1998; 84(3): 761 - 762. [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |