Thermoregulatory responses of a hibernator to hypothalamic and ambient temperatures

Steven H. Mills, Virginia M Miller, Frank E. South

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Abstract

Local cooling or heating of the hypothalamus of yellow bellied marmots elicited appropriate thermoregulatory responses to maintain body temperature. Increases in EMG, heart rate, and oxygen consumption were observed during hypothalamic cooling. Conversely, hypothalamic heating generally decreased thermogenic parameters toward minimal levels. Normothermic marmots retained thermoregulatory heat production throughout the year although loss of vasomotor regulation seemed to occur as they prepared for hibernation. The relationship between manipulated changes in hypothalamic temperature and induced changes in oxygen consumption was linear. This proportional relationship at one air temperature (15 °C) was parallel and displaced to the right of that relationship obtained at a lower air temperature (10 °C). These results are consistent with the hypothesis that hypothalamic regulation of body temperature in normothermic marmots is similar to that of nonhibernating mammals, although vasomotor regulation may differ.

Original languageEnglish (US)
Pages (from-to)465-472
Number of pages8
JournalCryobiology
Volume11
Issue number5
DOIs
StatePublished - 1974
Externally publishedYes

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ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

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