Expressão da oxido nitrico sintase em musculo esqueletico de ratos cronicamente tratados com L-NAME : estudos histoenzimologicos, bioquimicos e imunohistoquimicos
AUTOR(ES)
Angela Cristina Ito
DATA DE PUBLICAÇÃO
2005
RESUMO
Nitric oxide (NO) is a short-lived gas molecule that modulates neurotransmission, contractile force, glucose metabolism, vascular tone, and muscle function in general. Skeletal muscle is a major source of NO in mammals and expresses all three isoforms of NO synthases (NOS). Inhibitors of the NOS are useful tools for studying the role of NO in muscle physiology. In this work, we examined the effects of chronic treatment of rats with N?-nitro- L-arginine methyl ester (L-NAME), which blocks the synthesis of NO by NOSs, through selected biochemical and morphological parameters of soleus and extensor digitorum longus muscles. Fiber typing, fiber cross-sectional area, expression of myosin isoforms, number of muscle fiber nuclei, and the expression and immunolocalization of endothelial and neuronal NOS were used to assess the effects of NO deprivation. Rats were treated with L-NAME (20 mg/rat/day, in the drinking water) for two, four and eight weeks, after which the animals were sacrificed and the muscles removed and processed for analysis. The chronic treatment of rats with L-NAME caused a slight (13.2%) but significant decrease in the percentage of type I fibers after two weeks of treatment and in the cross-sectional area of IID fibers after eight weeks of treatment in soleus muscle. There were no significant differences in the percentage of fiber types or in their cross-sectional areas in the EDL. The number of muscle fiber nuclei, also used as an indicator of hypertrophy, did not show significant differences in the treated rats. Likewise, there were no significant changes in the expression and distribution of endothelial and neuronal NOS, or in the expression of myosin isoforms. These results show that the chronic inhibition of NO biosynthesis by L-NAME in the time intervals examined, generally did not alter the various parameters studied in rat soleus and extensor digitorum longus muscles, except for type I and IID fibers in soleus muscle
ASSUNTO(S)
musculo esqueletico oxido nitrico fibras musculares - tipos l-name
ACESSO AO ARTIGO
http://libdigi.unicamp.br/document/?code=vtls000348975Documentos Relacionados
- Atividades e expressão de peptidases em ratos tratados cronicamente com L-NAME, um inibidor da biossintese de oxido nitrico, e em ratos espontaneamente hipertensos
- Medida da atividade da enzima conversora de angiotensina I em orgãos de ratos tratados cronicamente com L-NAME
- Alterações morfologicas e atividades e expressão de citocromos P450 no figado de ratos tratados com L-NAME
- Efeitos do Rut-bpy (Cis-[Ru(bpy)2(SO3)(NO)]PF 6), um novo doador de óxido nítrico, na hipertensão induzida com L-NAME em ratos
- Treinamento resistido controla a pressão arterial de ratos hipertensos induzidos por l-NAME