FACTORS REGULATING PROPERTIES OF SKELETAL MUSCLE

未成熟大鼠骨骼肌的收缩和生化特性 成年动物依赖于肌肉的活动模式， 符合正常的功能需求。之间的关系 特定的蛋白质组成和个体的收缩特性 人们开始了解肌肉细胞。然而，生理 调节肌原纤维蛋白组成的因子，因此， 在发育过程中和成年肌肉中的收缩特性不太好 明白本项目的长期目标是确定 这些因子在调节骨骼肌活动中是重要的， 这些因素对收缩性和 单个肌肉细胞的生化特性。的活性 骨骼肌将使用功能过载进行实验性改变， 后肢悬吊诱导运动功能减退和慢性原位刺激 使用不同的电刺激模式。收缩和 将对转化后的肌肉进行生化测量， 与对照组的肌肉相比。收缩性能是 研究了最大缩短速度、张力产生的速度、张力的大小等 能力和张力/豌豆关系的单一，皮肤肌肉纤维。的 蛋白质组成将使用超灵敏凝胶 单克隆抗体电泳和免疫印迹技术 针对特定的肌球蛋白重链。测量将在 单个肌肉纤维的表面膜已经被去除， 化学结皮过程，以允许直接控制活化， Ca2+。在那些单个纤维太小而不能 令人满意的测量（例如，胚胎肌肉），整个肌肉将 研究了实验的设计将允许确定 分子结构与功能的关系 特定收缩特性与蛋白质之间的关系 发育中的、成年的和转化的肌肉的组成 骨骼肌的适应性 功能需求（如在长期锻炼期间）应该改善我们的 了解骨骼肌的生理调节 性能这些信息对设计来说应该是非常有价值的 用于促进或恢复运动功能的 在某些临床情况下。

Contractile and biochemical properties of skeletal muscles of immature and adult animals are dependent on the activity patterns of the muscles in accordance with normal functional demands. The relationships between specific protein compositions and the contractile properties of individual muscle cells are beginning to be understood. However, the physiological factors that regulate myofibrillar protein composition and, therefore, contractile properties during development and in adult muscle are less well understood. The long-term goal of this project is to determine which factors are important in the regulation of skeletal muscle activity and the effects that these factors have on the expression of contractile and biochemical characteristics of single muscle cells. The activity of skeletal muscle will be experimentally altered using functional overload, hindlimb suspension to induce hypokinesia and chronic in situ stimulation using different patterns of electrical stimulation. Contractile and biochemical measurements will be made on transformed muscles and compared to those obtained from control muscles. The contractile properties to be studied are the maximal velocity of shortening, the tension generating ability and tension/pea relationships of single, skinned muscle fibers. The protein composition will be assessed using ultrasensitive gel electrophoresis and immunoblotting techniques with monoclonal antibodies against specific myosin heavy chains. Measurements will be performed on single muscle fibers that have had their surface membranes removed using a chemical skinning procedure to allow direct control of activation with Ca2+. In those cases where the individual fibers are too small for satisfactory measurements (e.g., embryonic muscle), whole muscles will be studied. The design of the experiments will permit the determination of molecular structure-function relationships in muscle by identifying associations between specific contractile properties and protein compositions of developing, adult and transformed muscle An examination of the adaptability of skeletal muscle In response to alterations in functional demands (as during chronic exercise) should improve our understanding of the physiological regulation of skeletal muscle performance. This information should be extremely valuable for the design of neural prostheses which are used to facilitate or restore motor function in certain clinical situations.