Abstract
Administration of adenosine-5′-monophosphate (5′-AMP) can induce an artificial but endogenously reversible torpor-like state in mice. The dynamics of body temperature and the relation between body temperature and metabolic rate may indicate the (dis)similarity of this artificial torpor-like state to natural torpor in intact animals. We investigated these in C57BL/6J mice by (1) comparing cooling rates during 5′-AMP induced hypothermia to cooling rates during high workload induced torpor, and by (2) estimating the relative contributions of metabolic suppression and passive temperature (Q 10) effects in the 5′-AMP induced hypothermic state. We did the latter by back-extrapolating the relation between body temperature and metabolic rate in hypothermic conditions to the euthermic temperature level, using calculated Q 10-values. The data indicate that (1) cooling rate in 5′-AMP induced hypothermia is about 1.8 times faster than in natural torpor in workload conditions, and that (2) Q 10 effects can entirely explain the metabolic reduction of 5′-AMP induced hypothermia, indicating that active metabolic suppression may be lacking. Together, this suggests fundamental differences between 5′-AMP induced hypothermia and natural torpor, limiting the validity of the paradigm to the study of effects of hypothermic conditions and temperature related metabolic effects.
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Strijkstra, A.M., Koopmans, T., Bouma, H.R., de Boer, S.F., Hut, R.A., Boerema, A.S. (2012). On the Dissimilarity of 5′-AMP Induced Hypothermia and Torpor in Mice. In: Ruf, T., Bieber, C., Arnold, W., Millesi, E. (eds) Living in a Seasonal World. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-28678-0_31
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DOI: https://doi.org/10.1007/978-3-642-28678-0_31
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