Interactions among metabolic rate, hypoxia and control of
breathing.
Gautier, Henry.
Atelier de Physiologie Respiratoire, Facult[acute]e de
M[acute]edecine Saint-Antoine, 75012 Paris, France
APStracts 3:0100A, 1996.
This review attempts to emphasize the fact that the interpretation of
the ventilatory response to hypoxia may be complicated by the
reduction in metabolic rate which is often associated with hypoxia.
The hypoxic-hypometabolism is more apparent when VO2 is relatively
high, either in small or young mammals at subnormal ambient
temperatures or in larger mammals exposed to cold. This
hypometabolism is not mediated by an activation of the arterial
chemoreceptors and furthermore may result from a decrease in CaO2
independent of the PaO2. Several experimental evidences support the
hypothesis of a lowering of the thermo-regulatory setpoint during
hypoxia through a direct action on central neural structures. The
ventilatory response to hypoxia which may appear blunted or
depressed, especially in small animals exposed to cold, should in
fact be re-evaluated taking into account the hypometabolism and
hypothermia associated with hypoxia. Finally, it is emphasized that
the mechanisms which are involved in control of body temperature and
those which account for the interactions with hypoxia are located in
the hypothalamus. This suggests that common integrative structures
are probably involved in the metabolic and ventilatory response to
hypoxia.
Received 1 February 1996; accepted in final form 1 February 1996.
APS Manuscript Number A136-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 14 February 96