Summary
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1.
Isometric twitch tension development was measured over a wide range of temperatures in skeletal and cardiac (ventricular) muscles from diverse Australian lizards representing several families and including both diurnal and nocturnal species.
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2.
The temperatures at which maximal twitch tension develops (optimal temperatures) in the skeletal muscles is higher, by about 10–15° C, than in the ventricular muscles from the same species. Resistance to heat damage (thermostability) is similar for the two tissues.
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3.
Interspecific divergence is evident in the optimal temperatures and thermostabilities of both muscles, and these tissue differences parallel the preferred body temperatures of the species from which they are taken. In several nocturnal lizards (geckos) that have high preferred body temperatures, the thermal adjustments of the muscles resemble those of diurnal species, whereas muscles from geckos with low preferenda have relatively low optimal temperatures.
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4.
Variations in the heat resistance of the tissues correlate with variations in organismal heat resistance and in general, lethal temperatures for excised muscles and organism are similar.
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5.
These data are interpreted as indicating that divergence in the thermal adjustments for contractility of muscular tissues are most directly associated with the temperatures characteristically maintained through the behavior of the species rather than to the general geographical (climatic) distribution or phylogenetic position of the species.
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References
Dawson, W. R.: Physiological responses to temperature in the lizard Eumeces obsoletus. Physiol. Zool. 33, 87 (1960).
—: Interspecific variation in physiological responses of lizards to temperature. In: W. W. Milstead (ed.), Lizard Ecology Symposium, Univ. Mo. Press, Columbia, p. 230 (1967).
— and G. A. Bartholomew: Metabolic and cardiac responses to temperature in the lizard Dipsosaurus dorsalis. Physiol. Zool. 31, 100 (1958).
Licht, P.: A comparative study of the thermal dependence of contractility in saurian skeletal muscle. Comp. Biochem. Physiol. 13, 27 (1964).
—: Thermal adaptation in the enzymes of lizards in relation to preferred body temperatures. In: Molecular Mechanisms of Temperature Adaptation, p. 131. London-New York: Academic Press 1967.
Licht, P.: Response of the thermal preferendum and heat resistance to thermal acclimation under different photoperiods in the lizard Anolis carolinensis. Amer. Midland Nat. 79, 149 (1968).
— and S. L. Basu: Influence of temperature on lizard testes. Nature (Lond.) 213, 672 (1967).
—, W. R. Dawson, V. H. Shoemaker, and A. R. Main: Observations on the thermal relations of Western Australian lizards. Copeia 1966, 97 (1966a).
—: Heat resistance of some Australian lizards. Copeia 1966, 162 (1966b).
Ushakov, B. P.: Eine zytophysiologische Analyse der Anpassung der Reptilien an das Leben in der Wüste Karakum: Zool. Jb. 87, 507 (1960).
—: Thermostability of cell and proteins of poikilotherms and its significance in speciation. Physiol. Rev. 44, 518 (1964).
—: The problem of associated changes in protein thermostability during the process of speciation. Helgoländer wiss. Meeresunters. 14, 466 (1966).
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Licht, P., Dawson, W.R. & Shoemaker, V.H. Thermal adjustments in cardiac and skeletal muscles of lizards. Z. Vergl. Physiol. 65, 1–14 (1969). https://doi.org/10.1007/BF00297986
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DOI: https://doi.org/10.1007/BF00297986