Mitochondrial calcium oscillations in C2C12 myotubes.

Détails

ID Serval
serval:BIB_19528
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Mitochondrial calcium oscillations in C2C12 myotubes.
Périodique
Journal of Biological Chemistry
Auteur(s)
Challet C., Maechler P., Wollheim C.B., Ruegg U.T.
ISSN
0021-9258
Statut éditorial
Publié
Date de publication
2001
Volume
276
Numéro
6
Pages
3791-3797
Langue
anglais
Résumé
Mitochondrial Ca(2+) concentration ([Ca(2+)](m)) was monitored in C2C12 skeletal muscle cells stably expressing the Ca(2+)-sensitive photoprotein aequorin targeted to mitochondria. In myotubes, KCl-induced depolarization caused a peak of 3.03 +/- 0.14 micrometer [Ca(2+)](m) followed by an oscillatory second phase (5.1 +/- 0.1 per min). Chelation of extracellular Ca(2+) or blockade of the voltage-operated Ca(2+) channel attenuated both phases of the KCl response. The inhibitor of the sarcoplasmic reticulum Ca(2+)-ATPase, cyclopiazonic acid, reduced the amplitude of the KCl-induced [Ca(2+)](m) peak and prevented the oscillations, suggesting that these were generated intracellularly. No such [Ca(2+)](m) oscillations occurred with the nicotinic agonist carbachol, cyclopiazonic acid alone, or the purinergic agonist ATP. In contrast, caffeine produced an oscillatory behavior, indicating a role of ryanodine receptors as mediators of the oscillations. The [Ca(2+)](m) response was desensitized when cells were exposed to two consecutive challenges with KCl separated by a 5-min wash, whereas a second pulse of carbachol potentiated [Ca(2+)](m), indicating differences in intracellular Ca(2+) redistribution. Cross-desensitization between KCl and carbachol and cross-potentiation between carbachol and KCl were observed. These results suggest that close contacts between mitochondria and sarcoplasmic reticulum exist permitting Ca(2+) exchanges during KCl depolarization. These newly demonstrated dynamic changes in [Ca(2+)](m) in stimulated skeletal muscle cells might contribute to the understanding of physiological and pathological processes in muscular disorders.
Mots-clé
Animals, Calcium/metabolism, Cell Line, Mice, Mitochondria/metabolism, Muscle, Skeletal/cytology, Muscle, Skeletal/drug effects, Potassium Chloride/pharmacology
Pubmed
Open Access
Oui
Création de la notice
19/11/2007 10:41
Dernière modification de la notice
20/08/2019 13:50
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