Difference between revisions of "Staples 2010 Abstract IOC60"
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|event=IOC60 | |event=IOC60 | ||
|abstract=During entrance into a [[torpor]] bout the whole-animal metabolic rate of mammalian hibernators can decrease by up to 100-fold within a matter of hours. This metabolic suppression corresponds with a rapid decrease in succinate-fuelled State 3 respiration rates of liver mitochondria, measured at 37 °C. When isolated from 13-lined ground squirrel (''Ictodomys tridecemlineatus'') in early entrance (''T''b=30 °C), respiration decreased by 61% compared with interbout euthermia. Respiration did not decline further in late entrance (''T''b=15 °C) or steady-state torpor (''T''b=5 °C). In contrast, during early arousal (''T''b=15 °C), despite rapid increases in metabolic rate, State 3 respiration did not increase significantly from torpor levels. By the time ''T''b reached 30 °C in late arousal, however, respiration was 3-fold higher than torpor and continued to increase gradually, so that in interbout euthermia it was 6-fold higher than torpor and not significantly different from the summer active state. Preincubation with 2 mM isocitrate (removing oxaloacetate inhibition of succinate dehydrogenase) increased respiration only in torpor and early arousal. The “fast” initiation of mitochondrial metabolic suppression during entrance and its “slow” reversal during arousal suggests a mechanism that requires fairly high body temperatures. | |abstract=During entrance into a [[torpor]] bout the whole-animal metabolic rate of mammalian hibernators can decrease by up to 100-fold within a matter of hours. This metabolic suppression corresponds with a rapid decrease in succinate-fuelled State 3 respiration rates of liver mitochondria, measured at 37 °C. When isolated from 13-lined ground squirrel (''Ictodomys tridecemlineatus'') in early entrance (''T''b=30 °C), respiration decreased by 61% compared with interbout euthermia. Respiration did not decline further in late entrance (''T''b=15 °C) or steady-state torpor (''T''b=5 °C). In contrast, during early arousal (''T''b=15 °C), despite rapid increases in metabolic rate, State 3 respiration did not increase significantly from torpor levels. By the time ''T''b reached 30 °C in late arousal, however, respiration was 3-fold higher than torpor and continued to increase gradually, so that in interbout euthermia it was 6-fold higher than torpor and not significantly different from the summer active state. Preincubation with 2 mM isocitrate (removing oxaloacetate inhibition of succinate dehydrogenase) increased respiration only in torpor and early arousal. The “fast” initiation of mitochondrial metabolic suppression during entrance and its “slow” reversal during arousal suggests a mechanism that requires fairly high body temperatures. | ||
|keywords= | |keywords=Hibernation, Mitochondria, Ictidomys, Ground squirrel | ||
|discipline=Mitochondrial Physiology | |discipline=Mitochondrial Physiology | ||
|articletype=Workshop, MiPNet-online Publication | |articletype=Workshop, MiPNet-online Publication | ||
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}} | }} | ||
{{Labeling | {{Labeling | ||
|organism= | |organism=Mammals | ||
|tissues=Hepatocyte; Liver | |tissues=Hepatocyte; Liver | ||
|preparations=Isolated Mitochondria | |preparations=Isolated Mitochondria | ||
|enzymes=Complex II; Succinate Dehydrogenase | |enzymes=Complex II; Succinate Dehydrogenase | ||
|kinetics=Temperature | |kinetics=Temperature | ||
|discipline=Mitochondrial Physiology | |discipline=Mitochondrial Physiology | ||
|articletype=Workshop, MiPNet-online Publication | |articletype=Workshop, MiPNet-online Publication | ||
Revision as of 14:48, 13 February 2013
| Staples J, Chung D, Armstrong C (2010) Fast in, slow out: Kinetics of mitochondrial metabolic suppression during hibernation entrance and arousal. MiPNet15.10. |
Link: http://www.uwo.ca/biology/Faculty/staples/index.htm
Staples J, James F, Chung D, Armstrong C (2010)
Event: IOC60
During entrance into a torpor bout the whole-animal metabolic rate of mammalian hibernators can decrease by up to 100-fold within a matter of hours. This metabolic suppression corresponds with a rapid decrease in succinate-fuelled State 3 respiration rates of liver mitochondria, measured at 37 °C. When isolated from 13-lined ground squirrel (Ictodomys tridecemlineatus) in early entrance (Tb=30 °C), respiration decreased by 61% compared with interbout euthermia. Respiration did not decline further in late entrance (Tb=15 °C) or steady-state torpor (Tb=5 °C). In contrast, during early arousal (Tb=15 °C), despite rapid increases in metabolic rate, State 3 respiration did not increase significantly from torpor levels. By the time Tb reached 30 °C in late arousal, however, respiration was 3-fold higher than torpor and continued to increase gradually, so that in interbout euthermia it was 6-fold higher than torpor and not significantly different from the summer active state. Preincubation with 2 mM isocitrate (removing oxaloacetate inhibition of succinate dehydrogenase) increased respiration only in torpor and early arousal. The “fast” initiation of mitochondrial metabolic suppression during entrance and its “slow” reversal during arousal suggests a mechanism that requires fairly high body temperatures.
• Keywords: Hibernation, Mitochondria, Ictidomys, Ground squirrel
Labels:
Organism: Mammals"Mammals" is not in the list (Human, Pig, Mouse, Rat, Guinea pig, Bovines, Horse, Dog, Rabbit, Cat, ...) of allowed values for the "Mammal and model" property.
Tissue;cell: Hepatocyte; Liver"Hepatocyte; Liver" is not in the list (Heart, Skeletal muscle, Nervous system, Liver, Kidney, Lung;gill, Islet cell;pancreas;thymus, Endothelial;epithelial;mesothelial cell, Blood cells, Fat, ...) of allowed values for the "Tissue and cell" property.
Preparation: Isolated Mitochondria"Isolated Mitochondria" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property.
Enzyme: Complex II; Succinate Dehydrogenase"Complex II; Succinate Dehydrogenase" is not in the list (Adenine nucleotide translocase, Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase, Inner mt-membrane transporter, Marker enzyme, Supercomplex, TCA cycle and matrix dehydrogenases, ...) of allowed values for the "Enzyme" property.
Event: IOC60"IOC60" is not in the list (A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, ...) of allowed values for the "Event" property.
