CALCIUM REMOVAL AND REGULATION OF MUSCLE FUNCTION

钙的去除和肌肉功能的调节

• 批准号: 2272447
• 负责人: MARTIN F SCHNEIDER
• 金额: $ 17.97万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-05-01 至 1998-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2272447
• 关键词: Anura; action potentials; biological transport; calcium binding protein; calcium flux; calcium indicator; calcium transporting ATPase; computer simulation; digital imaging; electrostimulus; enzyme activity; fluorescence microscopy; gene mutation; isozymes; laboratory rabbit; laboratory rat; magnesium; muscle function; phosphoproteins; sarcoplasmic reticulum; striated muscles; tissue /cell culture; voltage /patch clamp

Depolarization of a skeletal muscle fiber causes calcium ions to be released from the sarcoplasmic reticulum (SR), the internal calcium- sequestering membrane system in muscle. The resulting elevated myoplasmic [Ca2+] enables contractile activity by binding to thin filament troponin C, which removes the inhibition of interaction between the thick and thin filaments. Elevated [Ca2+] also activates a variety of other [Ca2+] dependent regulatory changes in the fiber. On repolarization calcium release stops, [Ca2+] declines, calcium dissociates from troponin C and the muscle relaxes. The properties and functional roles of calcium binding proteins and the SR calcium pump in lowing [Ca2+] will be studied using two [Ca2+] indicators in voltage clamped single skeletal fibers from frog, rat and rabbit. The role of the soluble calcium and magnesium binding protein parvalbumin will be determined by comparing both the decline of [Ca2+] and the [Mg2+] transient in parvalbumin-containing and -lacking mammalian fast- and slow-twitch fibers. Modulation of the SR calcium pump in slow-twitch fibers by the SR protein phospholamban will be evaluated. The fast and slow phases of decline of [Ca2+] after various patterns of action potentials in each fiber type will be determine and the implications for [Ca2+] dependent regulation will be considered. The possible role of cytosolic [Ca2+] in altering fiber type during long-term electrical stimulation of tissue cultured fast- and slow-twitch fibers will be examined. Ca2+ indicators in the ER of cell lines transfected with various isoforms of the SR calcium pump or mutants thereof will be used to image [Ca2+] and changes in [Ca2+] within the internal stores to evaluate pump function in a simplified environment. [Ca2+] will also be monitored within the SR of muscle fibers to evaluate the roles of internal and external [Ca2+] in the function of the calcium pump in its normal environment. A variety of preparative, electrical, optical and computer analysis and modelling procedures previously developed and used in this laboratory will be combined with various tissue culture, molecular biological and digital imaging and image analysis techniques that are new to our lab. The results of these studies may provide basic information relevant to pathologic conditions and possible therapeutic interventions in various muscular, neuro-muscular or cardiac disease states.

骨骼肌纤维的去极化会导致钙离子为 从肌质网（SR）释放，内部钙 - 在肌肉中隔离膜系统。 由此产生的升高 肌质[Ca2+]通过与薄的结合来实现收缩活动 细丝肌钙蛋白C，它消除了对相互作用的抑制 厚而薄的细丝。 升高的[Ca2+]也激活了一种品种 纤维中其他[Ca2+]的依赖性调节变化。 在 复极化钙释放停止，[Ca2+]下降，钙 从肌钙蛋白C中解离，肌肉放松。 属性和 钙结合蛋白和SR钙泵的功能作用 将使用两个[Ca2+]电压中的两个[Ca2+]指示器研究降低[Ca2+] 夹紧青蛙，大鼠和兔子的单个骨骼纤维。角色 可溶性钙和镁结合蛋白白蛋白将是 通过比较[Ca2+]和[Mg2+]的下降来确定 在含白蛋白白蛋白的瞬时和斑点的哺乳动物快速及其瞬态 慢速纤维。 在慢速交换中调节SR钙泵 将评估SR蛋白磷酸纤维的纤维。 快速和 各种作用模式后，[Ca2+]下降的慢阶段 每种纤维类型中的电势将被确定以及对 [CA2+]将考虑依赖性调节。 可能的作用 长期电气期间改变纤维类型的胞质[Ca2+] 刺激组织培养的快速和慢速纤维将是 检查。 Ca2+指示器中的ER中转染的细胞系 将使用SR钙泵或其突变体的各种同工型 图像[Ca2+]和内部存储中[Ca2+]的变化 在简化的环境中评估泵功能。 [Ca2+]也将 在肌肉纤维的SR中进行监测，以评估 钙泵功能中的内部和外部[Ca2+] 正常环境。 各种准备，电气，光学和 以前开发和使用的计算机分析和建模程序 在这个实验室将与各种组织培养相结​​合， 分子生物学和数字成像和图像分析技术 这是我们实验室的新事物。 这些研究的结果可能会提供基本 与病理状况和可能治疗有关的信息 干预各种肌肉，神经肌肉或心脏病 国家。