REGULATION OF TRACHEAL SMOOTH MUSCLE CONTRACTION

这项研究的目的是确定 气管平滑肌收缩。 流行的模式是， 激动剂诱导的胞质游离Ca 2+增加导致激活 肌球蛋白轻链激酶。 的 肌球蛋白轻链（MLC）的磷酸化被认为是 引发和维持收缩的主要事件。 最近的数据 表明游离Ca 2+和MLC磷酸化的增加都不 反对有效 基于醛固酮的激素调节研究 分泌，以及在血管和气管平滑肌中的初步研究， 我们建立了钙信使系统的两相模型 在持续的细胞反应中发挥作用。 一系列实验 计划在气管平滑肌中测试该模型，分析：1） 卡巴胆碱对聚磷脂酰肌醇周转的影响， 肌醇三磷酸和二酰基甘油; 2）细胞的时间过程 和胞质溶胶蛋白磷酸化; 3） 所述试剂的作用特异性地：a）增加细胞内游离 Ca 2+（A23187或离子霉素）; B）激活C-激酶（TPA、OAG和其他 佛波醇酯）;和/或c）增加质膜Ca 2+（BAY K 8644）对 收缩反应的时间进程和细胞蛋白质 磷酸化; 4）细胞内游离Ca 2+的时程变化， 对卡巴胆碱和这些药物的反应; 5）卡巴胆碱的作用 和药物组合对C-激酶的细胞内分布的影响;和6） C-激酶的磷蛋白产物对 “化学皮肤”平滑肌的收缩反应。 分析 毛喉素，一种腺苷酸环化酶的激活剂， 会导致激动剂和药物引起的收缩松弛， 贯彻 作为计划研究的一部分，将制定方法， 活的激动剂反应性分离平滑肌细胞的分离 用于分析细胞Ca 2+代谢，以及 激动剂和药物引起的钙内流。 完成这些 这些目标将为平滑肌的分子基础提供新的见解， 收缩，这将是直接相关的临床问题， 支气管哮喘等气道平滑肌功能障碍状态。

The aim of the proposed research is to define the biochemical basis of tracheal smooth muscle contraction. The prevailing model is one in which an agonist-induced increase in cytosolic free Ca2+ leads to the activation of the calmodulin-dependent enzyme myosin light chain kinase. The resulting phosphorylation of the myosin light chain (MLC) is thought to be the major event in both initiating and sustaining contraction. Recent data show that neither the increase in free Ca2+ nor in MLC phosphorylation are sustained. Based on studies of the hormonal regulation of aldosterone secretion, and preliminary studies in vascular and tracheal smooth muscle, we have developed a two phase model of the calcium messenger system function during sustained cellular response. A series of experiments are planned to test this model in tracheal smooth muscle by analyzing: 1) the effect of carbachol on the turnover of the polyphosphatidylinositols, inositol triphosphate, and diacylglycerol; 2) the time course of cellular and cytosol protein phosphorylation in response to carbacholamine; 3) the effects of the agents which specifically: a) increase intracellular free Ca2+ (A23187 or ionomycin); b) activate C-kinase (TPA, OAG and other phorbol esters); and/or c) increase plasma membrane Ca2+ (BAY K 8644) on the time course of the contractile response, and cellular protein phosphorylation; 4) the time course change in intracellular free Ca2+ in response to carbacholamine and these drugs; 5) the effect of carbacholamine and drug combinations on the intracellular distribution of C-kinase; and 6) the effects of the phosphoprotein products of the C-kinase enzyme on the contractile responses of 'chemically skinned' smooth muscle. An analysis of the mechanism by which forskolin, an activator of adenylate cyclase, causes a relaxation of agonist-and drug-induced contractions will also be carried out. As part of the planned studies, methods will be developed for the isolation of viable, agonist-responsive isolated smooth muscle cells for use in the analysis of cellular Ca2+ metabolism, and initial rates of Ca2+ influx in response to agonist and drugs. Accomplishment of these goals would provide new insights into the molecular basis of smooth muscle contraction which would be directly relevant to the clinical problems of bronchial asthma and other states of airway smooth muscle dysfunction.