Hypothermia in hypoxic animals: Mechanisms, mediators, and functional significance

Stephen C. Wood, Rayna Gonzales

Research output: Contribution to journalArticle

70 Scopus citations

Abstract

A basic tenet of biology is that body temperature (T(b)) has a marked effect on oxygen uptake of resting animals. For most animals, the temperature coefficient (Q10) is ≥ 2.5; e.g., resting oxygen uptake changes about 11% per °C change in T(b). An important consequence of this dependence is that hyperthermia could be deleterious for hypoxic animals, particularly for oxygen sensitive organs, e.g., heart and brain. Conversely, a moderate degree of hypothermia could be beneficial during hypoxia. This concept is not new. Forced hypothermia is sometimes used in surgical procedures, particularly for heart and brain surgery. However, in many situations where hypothermia might have benefits, e.g., pediatric intensive care, it is not permitted. This is due in part to dogma and in part to the real and potential disadvantages of hypothermia, even in severely hypoxic animals. Among these is ventricular fibrillation. This is apparently preventable if blood pH is allowed to rise following the 'Buffalo Curve.' Another important disadvantage, were it to occur, is elevation of oxygen demand due to a thermogenic responses. However, at least in some species, the thermogenic response is blunted during hypoxia; e.g., in young rats. Furthermore, even if a thermogenic response occurs, this takes place primarily in muscles (shivering) and brown fat (non-shivering) and not in the O2-sensitive organs, heart and brain. A third disadvantage, for prolonged hypothermia, might be impairment of the immune response, a serious problem if hypoxia is combined with infection. This paper will review four aspects of behavioral fever and hypothermia: the occurrence among animals, the mechanisms and mediators that might trigger behavioral responses, and the functional significance.

Original languageEnglish (US)
Pages (from-to)37-43
Number of pages7
JournalComparative Biochemistry and Physiology - B Biochemistry and Molecular Biology
Volume113
Issue number1
DOIs
StatePublished - Jan 1 1996
Externally publishedYes

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Keywords

  • brain
  • hypothermia
  • hypoxia
  • respiration
  • thermoregulation

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Molecular Biology

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