Decreased rates of Ca(2+)-dependent heat production in slow- and fast-twitch muscles from the dystrophic (mdx) mouse.
Using a newly developed microcalorimetric approach to assess the rate of energy expenditure for intracellular [Ca2+] homeostasis in isolated muscles at rest, we found this was lower in mdx than in control mouse muscles, by 62% and 29% in soleus and extensor digitorum longus, respectively. Differences in total and Ca(2+)-dependent rates of specific heat production between mdx and control were enhanced during sustained, KCl-induced stimulation of energy dissipation. These results suggest that the low sarcoplasmic energy status of dystrophic muscles is not due to any excessive energy expenditure for intracellular [Ca2+] homeostasis.
Decrouy
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Département de Physiologie, Centre Médical Universitaire, Geneva, Switzerland.
Even
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Chinet
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D000818:Animals; D001693:Biological Transport, Active; D001833:Body Temperature Regulation; D002118:Calcium / Q000494:pharmacology*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004734:Energy Metabolism; D007700:Kinetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D009132:Muscles / Q000378:metabolism*; D009137:Muscular Dystrophy, Animal / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology
D013449:Sulfonamides; D010042:Ouabain; C017967:W 7; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium