FACTORS REGULATING PROPERTIES OF SKELETAL MUSCLE

幼年和成年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。两国之间的关系 特定的蛋白质组成和个体的收缩特性 肌肉细胞正开始被人们所理解。然而，生理上的 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 明白了。该项目的长期目标是确定 因子在调节骨骼肌活动中起着重要作用 这些因素对血管紧张素转换酶基因表达的影响 单个肌细胞的生化特征。的活动 骨骼肌将利用功能超负荷进行试验性改变， 后肢悬吊诱发运动功能减退和慢性原位刺激 使用不同模式的电刺激。可缩性和 将对转化后的肌肉进行生化测量并进行比较 从对照肌肉中获得的。收缩性能将是 研究了缩短的最大速度、张力的产生 单个脱皮肌肉纤维的能力和张力/豌豆关系。这个 蛋白质组成将使用超灵敏凝胶进行评估 单抗的电泳法和免疫印迹技术 对抗特定的肌球蛋白重链。测量将在以下位置执行 单个肌肉纤维的表面膜已经用一种 化学蒙皮程序，允许直接控制激活 Ca2+。在这些单独的纤维太小的情况下 令人满意的测量(例如，胚胎肌肉)，整个肌肉将 学习。实验的设计将允许确定 通过鉴定肌肉中的分子结构-功能关系 特定收缩特性与蛋白质之间的关系 发育期、成年期和转化期肌肉的组成 骨骼肌对不同生理状态变化的适应性 功能需求(就像在长期锻炼期间)应该会改善我们的 对骨骼肌生理调节的认识 性能。这些信息应该对设计非常有价值 用于促进或恢复运动功能的神经假体 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.