MECHANISM OF FORCE GENERATION & MAINTENANCE IN BLADDER--OULET OBSTRUCTION

力产生机制

• 批准号: 6346142
• 负责人: Robert S Moreland
• 金额: $ 18.13万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6346142
• 关键词: animal tissue; biological signal transduction; biomechanics; calcium flux; calcium ion; electrophysiology; human tissue; hypertrophy; lasers; mitogen activated protein kinase; muscle contraction; myosin light chain kinase; myosins; phosphorylation; photolysis; protein kinase C; smooth muscle; urethra disorder; urinary bladder; urinary bladder disorder

Obstruction of the urethra results in numerous alterations in the urinary bladder that impair both its storage and emptying properties. The detailed molecular mechanisms responsible for these changes in function associated with obstruction-induced remodeling that have not been clearly delineated. This research project is based upon the hypothesis that the depressed function of the obstructed bladder is the result of alterations in both excitation-contraction coupling (Ca2+-availability) and the contractile apparatus (Ca2+-sensitivity and Ca2+-dependent activity) in detrusor muscle. To test this hypothesis, the following specific aims will be addressed using strips of detrusor muscle obtained from normal, decompensated, and compensated rabbit bladder: Aim 1: To correlate the force-velocity length relations of intact and skinned detrusor muscle associated with bladder obstruction and its reversal. This aim will determine the mechanism of altered mechanics at the tissue, cell and cross-bridge level. Chemically skinned muscle strips allow for the precise and direct control of the environment surrounding the contractile apparatus, bypassing the normal excitation-contraction pathway. Aim 2: To determine the relationship among agonist concentration, cytoplasmic [Ca2+] and the time course of contraction. Laser photolysis of caged-compounds will be used to initiate contraction while monitoring the intracellular [Ca2+] with Indo-1. This aim will determine if the altered contractility is due to altered calcium mobilization. Aim 3: To determine the time course of myosin light chain phosphorylation, [Ca2+], and isometric force in intact and myosin light chain phosphorylation, actin-activated myosin ATPase activity and isometric force in permeabilized tissues during various stimuli. This aim will test for alteration in the coupling of the Ca2+ signal to contractile activation. Aim 4: To determine the significance of other regulatory signaling pathways. The protein kinase C, mitogen-activated protein kinase, caldesmon phosphorylation cascade will be measured. This aim will determine if the loss of maintained contractile force in the decompensated bladder is due to alterations in thin filament regulation. The results of these studies, in conjunction with those in Project 1, will elucidate the specific steps of excitation-contraction coupling that are associated with bladder dysfunction. Moreover, the results of these studies will also determine which alterations in contractile or regulatory proteins, in collaboration with Project 2, are associated with bladder remodeling and will provide a more complete understanding of the cellular and molecular mechanisms responsible for the depressed bladder function associated with outlet obstruction.

尿道阻塞导致泌尿系统的许多改变。 膀胱损害其存储和排空性能。的详细 负责这些功能变化的分子机制 梗阻引起的重塑还没有明确界定。 这项研究项目是基于这样一个假设，即抑郁症患者 梗阻膀胱的功能是两者改变的结果。 兴奋-收缩偶联（Ca 2 +-可用性）和收缩 逼尿肌中的Ca 2+敏感性和Ca 2+依赖性活动 肌肉.为了检验这一假设，将实现以下具体目标 使用从正常人， 失代偿和代偿的兔膀胱：目的1： 完整和去皮逼尿肌的力-速度长度关系 与膀胱梗阻及其逆转有关。这一目标将 确定在组织、细胞和组织中改变力学的机制， 跨桥水平。化学皮肤肌肉条允许精确的 并直接控制收缩肌周围的环境 装置，绕过正常的兴奋-收缩途径。目标2： 确定激动剂浓度、细胞质[Ca 2 +] 以及收缩的时间过程。笼状化合物的激光光解 将用于启动收缩，同时监测细胞内 [Ca2+]与Indo-1。这一目标将决定是否改变收缩力 是由于钙的动员发生了变化目标3：确定时间 肌球蛋白轻链磷酸化、[Ca 2 +]和等长力的过程 在完整和肌球蛋白轻链磷酸化中，肌动蛋白激活的肌球蛋白 透化组织中ATP酶活性和等长收缩力 各种刺激。这个目标将测试在耦合的改变， Ca 2+信号对收缩激活的影响。目标4：确定 其他调节信号通路的重要性。蛋白激酶C， 丝裂原活化蛋白激酶，钙调蛋白磷酸化级联反应将 被衡量。这一目标将决定是否保持收缩的损失 失代偿膀胱中的力是由于细丝的改变， 调控这些研究的结果，连同那些在 项目1，将阐明兴奋-收缩的具体步骤 与膀胱功能障碍相关的耦合。而且 这些研究的结果也将确定哪些改变， 收缩或调节蛋白，与项目2合作， 与膀胱重塑相关，并将提供更完整的 了解负责的细胞和分子机制， 与出口梗阻相关的膀胱功能抑制。