Thermoregulatory, carboxyatractylate-sensitive uncoupling in heart and skeletal muscle mitochondria of the ground squirrel correlates with the level of free fatty acids

• Published in: FEBS letters Vol. 305; no. 1; pp. 15 - 17
• Main Authors: Brustovetsky, N.N., Egorova, M.V., Gnutov, D.Yu, Gogvadze, V.G., Mokhova, E.N., Skulachev, V.P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 22-06-1992; Elsevier
• Subjects: 2,4-dinitrophenol; [ethylenebis(oxyethylenenitrilo)]-tetraacetic acid; Animals; Atractyloside - analogs & derivatives; Atractyloside - pharmacology; Biological and medical sciences; Body Temperature Regulation; bovine serum albumin; BSA; carboxyatractylate; CAtr; DNP; EDTA; EGTA; ethylenediaminetetraacetic acid; Fatty acid; Fatty Acids, Nonesterified - metabolism; Fundamental and applied biological sciences. Psychology; HEPE-S; Hibernation; Kinetics; Mitochondria, Heart - metabolism; Mitochondria, Liver - metabolism; Mitochondria, Muscle - metabolism; N-(2-hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid); Oligomycins - pharmacology; Organ Specificity; Oxidative Phosphorylation - drug effects; Sciuridae; Serum Albumin, Bovine - pharmacology; Thermoregulation. Hibernation. Estivation. Ecophysiology and environmental effects; Thermoregulatory uncoupling; Vertebrates: anatomy and physiology, studies on body, several organs or systems; BSA; CAtr; Thermoregulatory uncoupling; Fatty acid; Hibernation; HEPE-S; DNP; EDTA; EGTA; Heart; Vertebrata; Mitochondria; Mammalia; Decoupling; Oxidative phosphorylation; Rodentia; Thermoregulation; Striated muscle; Fatty acids; Cell respiration
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(92)80645-W

Thermoregulatory uncoupling of oxidative phosphorylation has been studied in heart and skeletal muscle mitochondria of ground squirrels. The respiratory rate of mitochondria in the presence of oligomycin was found to be much higher in winter (in hibernating, arousing, or aroused animals) than in summer. This additional respiration is strongly (arousing animals) or completely (hibernating and aroused animals) inhibited by carboxy-atractylate (CAtr) and bovine serum albumin (BSA). The CAtr- and BSA-induced decreases in the rate of respiration are accompanied by membrane potential increases. The rate of the CAtr- and BSA-sensitive respiration is proportional to the content of free fatty acids which, in the heart, decreases in the order: arousing > aroused = hibernating > summer animals. Maximal respiratory rates observed in the presence of dinitrophenol (arousing > aroused > summer > hibernating animals) do not parallel the fatty acid level. It is assumed that some heat production in the winter animals is due to fatty acid-induced, ATPIADP-antiporter-mediated uncoupling in heart and skeletal muscle mitochondria. The peak of heat production during arousal after hibernation also includes some other stimulatory effect on mitochondrial respiration.