Grimpo 2014 Comp Biochem Physiol A Mol Integr Physiol
| Grimpo K, Kutschke M, Kastl A, Meyer CW, Heldmaier G, Exner C, Jastroch M (2014) Metabolic depression during warm torpor in the Golden spiny mouse (Acomys russatus) does not affect mitochondrial respiration and hydrogen peroxide release. Comp Biochem Physiol A Mol Integr Physiol 167:7-14. |
Grimpo K, Kutschke M, Kastl A, Meyer CW, Heldmaier G, Exner C, Jastroch M (2014) Comp Biochem Physiol A Mol Integr Physiol
Abstract: Small mammals actively decrease metabolism during daily torpor and hibernation to save energy. Recently, depression of mitochondrial substrate oxidation in isolated liver mitochondria was observed and associated to hypothermic/hypometabolic states in Djungarian hamsters, mice and hibernators. We aimed to clarify whether hypothermia or hypometabolism causes mitochondrial depression during torpor by studying the Golden spiny mouse (Acomys russatus), a desert rodent which performs daily torpor at high ambient temperatures of 32°C. Notably, metabolic rate but not body temperature is significantly decreased under these conditions. In isolated liver, heart, skeletal muscle or kidney mitochondria we found no depression of respiration. Moderate cold exposure lowered torpor body temperature but had minor effects on minimal metabolic rate in torpor. Neither decreased body temperature nor metabolic rate impacted mitochondrial respiration. Measurements of mitochondrial proton leak kinetics and determination of P/O ratio revealed no differences in mitochondrial efficiency. Hydrogen peroxide release from mitochondria was not affected. We conclude that interspecies differences of mitochondrial depression during torpor do not support a general relationship between mitochondrial respiration, body temperature and metabolic rate. In Golden spiny mice, reduction of metabolic rate at mild temperatures is not triggered by depression of substrate oxidation as found in liver mitochondria from other cold-exposed rodents. • Keywords: Mitochondrial respiration, Daily torpor, Hypothermia, Hypometabolism, Acomys russatus, Amplex Red, TPMP
• O2k-Network Lab: DE Munich Jastroch M
Labels: MiParea: Respiration, Comparative MiP;environmental MiP
Stress:Temperature Organism: Other mammals Tissue;cell: Heart, Skeletal muscle, Liver, Kidney Preparation: Isolated mitochondria
Coupling state: LEAK, OXPHOS, ET
Pathway: S
