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Natural versus induced arousal from torpor: differences in fuel utilization and rewarming dynamics
Author(s) -
Thornton Doug K.,
Utz Jenifer C.,
Pan Peipei,
Yezhikov Dimitriy Y.,
Van Breukelen Frank
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.2_supplement.107
Subject(s) - torpor , arousal , hibernation (computing) , nefa , chemistry , medicine , biology , endocrinology , thermoregulation , neuroscience , state (computer science) , algorithm , computer science , insulin
During hibernation, animals oscillate between periods of torpor, when body temperatures are low and metabolism is depressed, and interbout arousal, when euthermic body temperatures are maintained and metabolic processes are more active. The process by which hibernators transition between the torpid and interbout aroused states is called arousal. Arousal from torpor happens naturally in response to endogenous cues. However, hibernators can also be induced to arouse prematurely in response to various disturbances. We investigated whether natural and induced arousals are synonymous events. Metabolite levels in blood, oxygen consumption, carbon dioxide production, and rewarming dynamics were compared between natural and induced arousals in order to address this question. Preliminary data indicate that plasma lactate concentrations are significantly higher during induced arousal than natural arousal (ANOVA; p < 0.05). No differences were found in glucose or free fatty acid concentrations (ANOVA; p > 0.05). We are currently analyzing data for respirometry measurements. Analysis of body temperature revealed differences in the timing of natural and induced arousals. The time required to complete an arousal and the time required to reach maximum rates of rewarming were significantly greater for induced arousals. However, there were no differences between groups for the maximum rewarming rate or the associated body temperature. Collectively, these data indicate that there are biologically relevant differences between natural and induced arousal from torpor and that data from studies using induced arousals should be interpreted with caution.