N-acetylcysteine fails to modulate the in vitro function of sarcoplasmic reticulum of diaphragm in the final phase of fatigue.
Acta Physiol Scand
; 184(3): 195-202, 2005 Jul.
Article
en En
| MEDLINE
| ID: mdl-15954987
AIM: In the present study, we tested the hypothesis whether N-acetylcysteine (NAC), a non-specific antioxidant, might influence fatigue by modulating Ca2+-handling capacity by the sarcoplasmic reticulum (SR). METHODS: In the presence (10 mm) or absence of NAC, bundles of rat diaphragm were stimulated with tetanic trains (350 ms, 30-40 Hz) at 1 train every 2 s for 300 s. SR functions, as assessed by SR Ca2+-uptake and release rates and SR Ca2+-ATPase activity, were measured in vitro on muscle homogenates. RESULTS: Following the 300-s stimulation, the force developed by NAC-treated muscles is approximately 1.8-fold higher (P < 0.05) than that of muscles without NAC treatment. Stimulation elicited an 18-30% depression in SR function (P < 0.05). Despite the differing degrees of fatigue between NAC-treated and non-treated muscles, SR functions in these muscles were reduced to similar extents. CONCLUSIONS: These results suggest that modulation of SR function measured in vitro may not be a major contributor to inhibition of diaphragmic fatigue with antioxidant, at least, in the final phase of fatigue where force output is remarkably reduced.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Acetilcisteína
/
Retículo Sarcoplasmático
/
Diafragma
/
Fatiga Muscular
/
Antioxidantes
Límite:
Animals
Idioma:
En
Revista:
Acta Physiol Scand
Año:
2005
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Reino Unido