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Hypothalamic thermosensitivity and regulation of heat storage behavior in a day-active desert rodentAmmospermophilus nelsoni

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Summary

  1. 1.

    The characteristics of hypothalamic thermosensitivity ofAmmospermophilus nelsoni were determined at three ambient temperatures by manipulating the temperature of the hypothalamus with chronically implanted, water-perfused thermodes while continuously measuring metabolic rate (Figs. 1, 2, and 3).

  2. 2.

    Hypothalamic thermosensitivity as measured by the proportionality constant for the heat production response to hypothalamic cooling (αMHP) was extremely high in the 6 individuals studied, averaging −5.1 watts kg−1 °C−1 at aT a of 10°C, −5.4 watts kg−1 °C−1 at 20°C, and −7.6 watts kg−1 °C at 30°C (Table 1).

  3. 3.

    The threshold hypothalamic temperature for the metabolic heat production response to hypothalamic cooling decreased asT a increased a veraging 42.2 °C at aT a of 10 °C, 40.9 °C at aT a of 20 °C, and 39.1 °C at aT a of 30 °C (Table 1).

  4. 4.

    High hypothalamic temperatures (>40 °C) induced a long-lasting suppression of the level at whichT b was regulated (Fig. 4). This fall inT b was associated with a decrease in αMHP or the hypothalamic threshold temperature for the metabolic heat production response (Figs. 5 and 6). It is hypothesized that these changes in the hypothalamic regulator of body temperature resulting from high hypothalamic temperatures are the physiological bases of the alleged heat storage thermoregulatory behavior of this small, day-active, desert mammal.

  5. 5.

    A neuronal model of the CNS thermoregulatory system is presented (Fig. 7) which offers possible explanations for the two unusual features of the antelope ground squirrel's thermoregulatory system descriged in this study, namely the increase in the absolute value of αMHP asT a increases and the suppression ofT b, αMHP, and the thresholdT hy for the metabolic heat production response following episodes of high hypothalamic temperature.

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References

  • Bligh, J.: The thermosensitivity of the hypothalamus and thermoregulation in mammals. Biol. Rev.41, 317–367 (1966)

    Google Scholar 

  • Bligh, J.: Neuronal models of mammalian temperature regulation. In: Essays on temperature regulation (eds. J. Bligh, R. Moore). New York: Academic Press 1972

    Google Scholar 

  • Bloom, F.E.: Dynamics of synaptic modulation: Perspectives for the future. In: The neurosciences third study program (eds. F.O. Schmitt, F.C. Worden), pp. 929–941. Cambridge, Mass: M.I.T. Press 1974

    Google Scholar 

  • Euler, C. von, Söderberg, U.: Co-ordinated changes in temperature thresholds for thermoregulatory reflexes. Acta Physiol. Scand.42, 112–129 (1958)

    Google Scholar 

  • Glotzbach, S.F., Heller, H.C.: CNS regulation of metabolic rat in the kangaroo ratDipodomys ingens. Amer. J. Physiol.228, 1880–1886 (1975)

    Google Scholar 

  • Hammel, H.T. Heller, H.C., Sharp, F.R.: Probing the rostral brainstem of anesthetized, unanesthetized, and exercising dogs and of hibernating and euthermic ground squirrels. Fed. Proc.32, 1588–1597 (1973)

    Google Scholar 

  • Hammel, H.T., Jackson, D.C., Stolwijk, J.A.J., Hardy, J.D., Strømme, S.B.: Temperature regulation by hypothalamic proportional control with adjustable set temperature. J. Appl. Physiol.18, 1146–1154 (1963)

    Google Scholar 

  • Heller, H.C., Colliver, G.W., Anand, P.: CNS regulation of body temperature in euthermic hibernators. Amer. J. Physiol.227, 576–582 (1974)

    Google Scholar 

  • Heller, H.C., Hammel, H.T.: CNS control of body temperature during hibernation. Comp. Biochem. Physiol.41A, 349–359 (1972)

    Google Scholar 

  • Heller, H.C., Poulson, T.L.: Altitudinal zonation of chipmunks (Eutamias): Adaptations to aridity and high temperature. Amer. Mid. Nat.87, 296–313 (1972)

    Google Scholar 

  • Hellstrøm, B., Hammel, H.T.: Some characteristics of temperature regulation in the unanesthetized dog. Amer. J. Physiol.213, 547–556 (1967)

    Google Scholar 

  • Hudson, J.W.: The role of water in the biology of the antelope ground squirrel,Citellus leucurus. U. Calif. Pub. Zool.64, 1–56 (1962)

    Google Scholar 

  • Jacobson, F.H., Squires, R.D.: Thermoregulatory responses of the cat to preoptic and environmental temperatures. Amer. J. Physiol.218, 1575–1582 (1970)

    Google Scholar 

  • Jessen, C.: Spinal and hypothalamic thermosensitivity in a conscious goat at two levels of air temperature. Biometeorology6, 19–20 (1975)

    Google Scholar 

  • Jessen, C., Mayer, E.Th.: Spinal cord and hypothalamus as core sensors of temperature in the conscious dog. I. Equivalence of responses. Pflügers Arch.324, 189–204 (1971)

    Google Scholar 

  • Kavanaugh, J.L., Rischer, C.E.: Influences of ambient temperature on ground squirrel activity. Ecology53, 158–164 (1972)

    Google Scholar 

  • Kramm, K.R.: Body temperature regulation and torpor in the antelope ground squirrel,Ammospermophilus leucurus. J. Mamm.53, 609–611 (1972)

    Google Scholar 

  • Mills, S.H., Miller, V.M., South, F.E.: Thermoregulatory responses of a hibernator to hypothalamic and ambient temperatures. Cryobiology11, 465–472 (1974)

    Google Scholar 

  • Stitt, J.T., Hardy, J.D., Stolwijk, J.A.J.: PGE1 fever: its effect on thermoregulation at different low ambient temperatures. Amer. J. Physiol.227, 622–629 (1974)

    Google Scholar 

  • Weight, F.F.: Physiological mechanisms of synaptic modulation. In: The neurosciences third study program (eds. F.O. Schmitt, F.C. Worden), pp. 989–999. Cambridge, Mass: M.I.T. Press 1974

    Google Scholar 

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Heller, H.C., Henderson, J.A. Hypothalamic thermosensitivity and regulation of heat storage behavior in a day-active desert rodentAmmospermophilus nelsoni . J Comp Physiol B 108, 255–270 (1976). https://doi.org/10.1007/BF00691674

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