RESUMO
The author makes comments about the shortening and loss of elasticity of the oculomotor muscle that remains slack for some time (contracture), by means of a reasoning based on the Hooke´s law and on the papers carried out to demonstrate that a muscle that remains relaxed for some time suffers a shortening due to loss of sarcomeres on the longitudinal direction and the increase of the cross-sectional area due to the increase of collagen tissue in the perimysium and the endomysium.
O autor procura demonstrar a razão da perda de elasticidade e do encurtamento do músculo oculomotor que permanece relaxado durante certo tempo (contratura), mediante raciocínio baseado na lei de Hooke e nos trabalhos que demonstram que o músculo oculomotor que permanece frouxo por algum tempo sofre encurtamento devido à perda de sarcômeros no sentido longitudinal e ao aumento da área da secção transversa, devida ao aumento do tecido colágeno do perimísio e do endomísio.
Assuntos
Humanos , Colágeno/fisiologia , Contratura/etiologia , Músculos Oculomotores/fisiologia , Sarcômeros/fisiologia , Elasticidade , Músculos Oculomotores/citologiaRESUMO
Skeletal muscles have the potential to regenerate by activation of quiescent satellite cells, however, the molecular signature that governs satellite cells during muscle regeneration is not well defined. Myosin light chains (Myls) are sarcomere-related proteins as traditional regulator of muscle contraction. In this report, we studied the possible role of Myl in the proliferation of skeletal muscle-derived myoblasts. Compared to diaphragm-derived myoblasts, the extraocular muscle-derived myoblasts with lower levels of Myl proliferated faster, maintained a longer proliferation phase, and formed more final myotubes. It was found that blockading Myl with anti-Myl antibody or knockdown of Myll by siRNA targeted against Myll could enhance the myoblast proliferation and delay the differentiation of myoblasts. Our results suggested that Myl, likely Myll, can negatively affect myoblast proliferation by facilitating myoblast withdrawal from cell cycle and differentiation.
Assuntos
Animais , Camundongos , Proliferação de Células , Diafragma/citologia , Mioblastos/fisiologia , Cadeias Leves de Miosina/fisiologia , Músculos Oculomotores/citologia , Regeneração/fisiologia , Western Blotting , Imuno-Histoquímica , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Los quimiorreceptores son estructuras específicas ampliamente distribuidas en el organismo. El cuerpo carotídeo es el representante principal de este sistema, por lo que es el mejor estudiado y sirve de punto de comparación para el conocimiento de otros quimiorreceptores. El quimiorreceptor ciliar ha sido identificado únicamente en aves, pero su estructura no ha sido descrita en detalle. Este trabajo representa una breve comunicación preliminar.