REGULATION OF CONTRACTILITY IN SMOOTH MUSCLE

平滑肌收缩力的调节

• 批准号: 3343991
• 负责人: KRISTINE E KAMM
• 金额: $ 9.92万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-07-01 至 1993-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3343991
• 关键词: adenosinetriphosphatase; biomechanics; calcium channel blockers; calmodulin; cow; elasticity; electrostimulus; enzyme mechanism; hormone regulation /control mechanism; muscle cells; muscle contraction; muscle pharmacology; myosin light chain kinase; myosins; neural information processing; neurotransmitters; phosphomonoesterases; phosphorylation; respiratory muscles; smooth muscle; tissue /cell preparation; trachea

The long-range goals of the research described in this application are to define intracellular processes regulating contractility in smooth muscle with emphasis on the mechanistic role for myosin phosphorylation, and eventually to define alterations in these processes associated with disease. The experiments described are designed (1) to improve mechanical estimates of contractility in smooth muscle tissues by measurement of complex stiffness, (2) to measure mechanical properties of skinned tracheal muscle under conditions where the composition of the medium surrounding the contractile elements can be controlled and altered and (3) to use these findings to investigate physiological modes of regulation of contractility in intact muscle. Elastic and viscous stiffness will be measured in tonically contracted bovine tracheal smooth muscle by analysis of the force amplitude and phase angle between force and applied sinusoidal length perturbations at a number of frequencies. This method will be used to test the hypothesis that the muscle exhibits an altered frequency response function for states in which myosin cross bridges are phosphorylated and rapidly cycling or dephosphorylated and slowly cycling (latch). A skinned tracheal smooth muscle preparation will be characterized. By measuring the dependence of force on calcium and calmodulin concentrations following dephosphorylation of myosin by addition of phosphatase or specific inhibitors of myosin light chain kinase (synthetic peptides) it will be determined if a latch state can be obtained in skinned trachealis. The frequency response function of the skinned muscle in rigor and latch will be compared to that in the living muscle. The ionic environment of the skinned muscle in latch will be manipulated to reproduce mechanical behavior observed in the intact muscle. The force-velocity relation will be measured in skinned fibers following treatments with myosin light chain kinase and/or protein kinase C in order to test the hypothesis that phosphorylation of specific combinations of amino acids on light chain can modulate crossbridge cycling rates differentially. The rate of inactivation of myosin light chain kinase, rate and kinetic mechanism of myosin dephosphorylation by phosphatase and rate of decline in stiffness will be measured in intact trachealis muscle which is rapidly relaxing from neurally stimulated contraction.

本应用程序中描述的研究的远程目标 要定义调节收缩性的细胞内过程 平滑肌，强调肌球蛋白的机械作用 磷酸化，并最终定义这些改变 与疾病相关的过程。 所述的实验是 设计（1）以提高收缩力的机械估计值 通过测量复杂刚度，平滑肌组织（2） 测量皮肤气管肌肉的机械性能 在介质组成的条件下 围绕收缩元素可以控制，并且 改变和（3）使用这些发现来研究生理 完整肌肉收缩力调节模式。 弹性和 粘性刚度将以色调收缩的牛来测量 通过分析力幅度和 力与施加的正弦长度之间的相角 许多频率的扰动。 这个方法将是 用于检验肌肉表现出改变的假设 肌球蛋白交叉的状态的频率响应功能 桥是磷酸化的，迅速骑自行车或 去磷酸化并缓慢循环（闩锁）。 皮肤气管 平滑肌肉的制备将被表征。 通过测量 力对钙和钙调蛋白的依赖性 通过添加的肌球蛋白去磷酸化后的浓度 磷酸酶或肌球蛋白轻链激酶的特异性抑制剂 （合成肽）将确定是否可以闩锁状态 在皮肤气管上获得。 频率响应函数 将皮肤的肌肉严格和闩锁与 在活着的肌肉中。 皮肤肌肉的离子环境 在闩锁中将被操纵以繁殖机械行为 在完整的肌肉中观察到。 力量关系将是 用肌球蛋白光治疗后，在皮肤纤维中测量 链激酶和/或蛋白激酶C，以测试 假设氨基特异性组合的磷酸化 轻链上的酸可以调节Crossbridge循环速率 差异。 肌球蛋白轻链激酶的失活率，速率和 肌球蛋白去磷酸化的动力学机理通过磷酸化酶脱磷酸化 刚度的下降速率将完整衡量 气管肌肉迅速从神经上放松 刺激收缩。