MHC isoform composition and Ca(2+)- or Sr(2+)-activation properties of rat skeletal muscle fibers.
Am J Physiol Cell Physiol
; 279(5): C1564-77, 2000 Nov.
Article
en En
| MEDLINE
| ID: mdl-11029304
Chemically skinned single fibers from adult rat skeletal muscles were used to test the hypothesis that, in mammalian muscle fibers, myosin heavy chain (MHC) isoform expression and Ca(2+)- or Sr(2+)-activation characteristics are only partly correlated. The fibers were first activated in Ca(2+)- or Sr(2+)-buffered solutions under near-physiological conditions, and then their MHC isoform composition was determined electrophoretically. Fibers expressing only the MHC I isoform could be appropriately identified on the basis of either the Ca(2+)- or Sr(2+)-activation characteristics or the MHC isoform composition. Fibers expressing one or a combination of fast MHC isoforms displayed no significant differences in their Ca(2+)- or Sr(2+)-activation properties; therefore, their MHC isoform composition could not be predicted from their Ca(2+)- or Sr(2+)-activation characteristics. A large proportion of fibers expressing both fast- and slow-twitch MHC isoforms displayed Ca(2+)- or Sr(2+)-activation properties that were not consistent with their MHC isoform composition; thus both fiber-typing methods were needed to fully characterize such fibers. These data show that, in rat skeletal muscles, the extent of correlation between MHC isoform expression and Ca(2+)- or Sr(2+)-activation characteristics is fiber-type dependent.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Estroncio
/
Calcio
/
Músculo Esquelético
/
Fibras Musculares Esqueléticas
/
Cadenas Pesadas de Miosina
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Am J Physiol Cell Physiol
Asunto de la revista:
FISIOLOGIA
Año:
2000
Tipo del documento:
Article
País de afiliación:
Australia
Pais de publicación:
Estados Unidos