Behavioral thermoregulation by hypoxic rats.
To address whether a shift in hypothalamic thermal setpoint might be a significant factor in induction of hypoxic hypothermia, behavioral thermoregulation was examined in 7 female Sprague-Dawley rats implanted with radiotelethermometers for deep body temperature (Tb) measurement in a thermocline during normoxia (PO2 = 125 torr) and hypoxia (PO2 = 60 torr). Normoxic rats (TNox) selected a mean ambient temperature of 19.7 +/- 1.4 (SE) degrees C and maintained Tb at 37.0 +/- 0.2 degrees C. Hypoxic rats selected a significantly higher ambient temperature (THox = 28.6 +/- 2.2 degrees C) but maintained Tb significantly lower at 35.5 +/- 0.3 degrees C. Without a thermal gradient (ambient temperature = 25 degrees C), Tb during hypoxia was 35.4 +/- 0.4 degrees C. The maintenance of a lower body temperature during hypoxia through behavioral thermoregulation despite having warmer temperatures available supports the hypothesis that the thermoregulatory setpoint of hypoxic rats is shifted to promote thermoregulation at a lower Tb, effectively reducing oxygen demand when oxygen supply is limited.
Dupré
R K
RK
Department of Biological Sciences, University of Nevada, Las Vegas 89154.
Owen
T L
TL
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology*; D005260:Female; D010100:Oxygen / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D010100:Oxygen