RESUMO
Fatigue, polarization level and excitability of striated muscle fibers from ischemia zone were studied on experimental rats under the tourniquet shock. It was established that violation-mediated contraction and fatigue of skeletal muscle was associated with a decrease in a number of muscle fibers with high level of MPP. The article discussed the mechanisms of fatigue and depolarization of muscle fibres in tourniquet shock.
Assuntos
Fadiga/fisiopatologia , Músculos/fisiopatologia , Choque/fisiopatologia , Animais , Fadiga/etiologia , Feminino , Membro Posterior/irrigação sanguínea , Isquemia/fisiopatologia , Masculino , Potenciais da Membrana , Contração Muscular , Ratos , Choque/etiologia , Fatores de Tempo , TorniquetesRESUMO
Injection of the sublethal dose of botulinic toxin into one of the masseter muscles produces muscle weakness and impaired occlusion. The membrane polarization rate and action potential decrease primarily in high polarized muscle fibers of the injured muscle. Meanwhile the function of low polarized fibers does not undergo any significant changes.
Assuntos
Botulismo/fisiopatologia , Músculo Masseter/fisiopatologia , Músculos da Mastigação/fisiopatologia , Contração Muscular , Animais , Modelos Animais de Doenças , RatosRESUMO
It was established by the method of intracellular lead of membrane rest potentials (MRP) and action potentials (AP) that fibers with high MRP and little overshot are mainly located in superficial layers of the rat masseter muscle proper whereas those with low MRP and high overshot principally in deep layers. Excitability of the cytoplasmic membrane of muscular fibers of both types proved to be related in electrical properties (critical level of depolarization, current threshold). It is suggested that the rat masseter muscle contains a great number of rapid phasic fibers in superficial layers and slow ones in deep layers.