AJP - Regulatory, Integrative and Comparative Physiology, Vol 260, Issue 1 120-R125, Copyright © 1991 by American Physiological Society

ARTICLES

Comparative effects of hypoxia on behavioral thermoregulation in rats, hamsters, and mice

C. J. Gordon and L. Fogelson
Neurotoxicology Division, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711.

Recent studies using reptiles and other ectothermic species have shown that hypoxia lowers the set point for the control of body temperature. This is characterized by a preference for cooler ambient (Ta) and deep body temperatures (Tb) when placed in a temperature gradient. To elucidate the presence of this effect in mammals, the selected Ta and Tb of three rodent species (mouse, hamster, and rat) were measured while subjected to graded hypoxia in a temperature gradient. Individual animals were placed in the gradient for 30 min. Oxygen content of air entering the gradient was then reduced to a constant level for a period of 60 min by dilution with nitrogen. Tb was significantly reduced in all species at %O2 levels of 5.5-10%. Selected Ta was significantly reduced in the mouse at %O2 levels of 5.5 and 7.3%. Selected Ta of the hamster and rat were reduced slightly at %O2 levels of 5.8 and 7.4%, respectively; however, the effect was not statistically significant. To clarify the effects of hypoxia in these two species, the sample size of rat and hamster was increased to strengthen statistical analysis, and the animals were exposed for 60 min to %O2 levels of 7.4 and 6.7%, respectively. Both species exhibited a significant reduction in selected Ta during hypoxia concomitant with hypothermia. These data support the hypothesis that hypoxia lowers the set point for the control of body temperature in rodents.

This article has been cited by other articles:

				R. C. H. Barros and L. G. S. Branco Central dopamine modulates anapyrexia but not hyperventilation induced by hypoxia J Appl Physiol, March 1, 2002; 92(3): 975 - 981. [Abstract] [Full Text] [PDF]

				G. J. Tattersall, J. L. Blank, and S. C. Wood Ventilatory and metabolic responses to hypoxia in the smallest simian primate, the pygmy marmoset J Appl Physiol, January 1, 2002; 92(1): 202 - 210. [Abstract] [Full Text] [PDF]

				M. Maskrey, P. R. Wiggins, and P. B. Frappell Behavioral thermoregulation in obese and lean Zucker rats in a thermal gradient Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2001; 281(5): R1675 - R1680. [Abstract] [Full Text] [PDF]

				R. C. H. Barros, M. E. Zimmer, L. G. S. Branco, and W. K. Milsom Hypoxic metabolic response of the golden-mantled ground squirrel J Appl Physiol, August 1, 2001; 91(2): 603 - 612. [Abstract] [Full Text] [PDF]

				H. Hamrahi, R. Stephenson, S. Mahamed, K. S. Liao, and R. L. Horner Physiological and Genomic Consequences of Intermittent Hypoxia: Selected Contribution: Regulation of sleep-wake states in response to intermittent hypoxic stimuli applied only in sleep J Appl Physiol, June 1, 2001; 90(6): 2490 - 2501. [Abstract] [Full Text] [PDF]

				B. Bishop, G. Silva, J. Krasney, H. Nakano, A. Roberts, G. Farkas, D. Rifkin, and D. Shucard Ambient temperature modulates hypoxic-induced changes in rat body temperature and activity differentially Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2001; 280(4): R1190 - R1196. [Abstract] [Full Text] [PDF]

				C. J Gordon The therapeutic potential of regulated hypothermia Emerg. Med. J., March 1, 2001; 18(2): 81 - 89. [Abstract] [Full Text]

				R. N. Rausch, L. I. Crawshaw, and H. L. Wallace Effects of hypoxia, anoxia, and endogenous ethanol on thermoregulation in goldfish, Carassius auratus Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2000; 278(3): R545 - R555. [Abstract] [Full Text] [PDF]

				E.-L. M. Rollins and J. E. Fewell Cerebral cortex does not modulate "regulated" decrease in core temperature during hypoxemia in rats Am J Physiol Regulatory Integrative Comp Physiol, April 1, 1998; 274(4): R1158 - R1161. [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]