PHOSPHODIESTERASE INHIBITION AND MUSCLE CONTRACTION

这个研究项目的目标是阐明一些基本的 控制冠状动脉收缩和增重的机制 对一般的平滑肌松弛药的作用机制的洞察， 尤其是黄嘌呤，可以放松平滑的肌肉。具体来说，我们 将开发确定肌球蛋白磷酸化程度的方法 轻链激酶在完整冠状动脉中的表达，并使用这些方法 松弛剂对磷酸化程度影响的研究 这种酶。我们还将确定肌球蛋白轻链激酶的活性 而磷酸二酯酶活性受钙调蛋白控制。 并测定牛冠状动脉及各种平滑肌的作用 松弛药对酶-钙调蛋白复合体水平的影响。此外, 我们将使用一种“去皮”的牛冠状动脉条 这是我们最近在实验室里开发的。我们会调查的 环核苷酸依赖的蛋白激酶是否会导致 松弛这些没有功能性肌膜的制剂以 防止大分子进入收缩系统。如果 激酶引起松弛，我们将努力识别底物 牵涉其中。我们还将使用“剥皮”的动脉条来尝试 按顺序确定可作用于该系统的平滑肌松弛剂 以确定可能作用于收缩系统或那些控制的药剂 系统在“去皮”准备过程中仍然起作用。

The goals of this research program are to elucidate some of the fundamental mechanisms that control contraction of coronary arteries and to gain insights into the mechanisms by which smooth muscle relaxants in general, and the xanthines in particular, can relax smooth muscle. Specifically, we will develop methods to determine the extent of phosphorylation of myosin light chain kinase in intact coronary arteries and use these methods to study the effect of relaxing agents upon the extent of phosphorylation of this enzyme. We will also determine if myosin light chain kinase activity and phosphodiesterase activities are controlled by calmodulin in the intact bovine coronary arteries and determine the effects of various smooth muscle relaxants on the levels of the enzyme-calmodulin complexes. In addition, we will utilize a "skinned" preparation of bovine coronary artery strips that we have recently developed in our laboratory. We will investigate whether the cyclic nucleotide dependent protein kinases will cause relaxation of these preparations that do not have a functional sarcolema to prevent access of large molecules to the contractile system. If the kinases cause relaxation, we will endeavor to identify the substrates involved. We will also use the "skinned" artery strips to attempt to identify smooth muscle relaxing agents that can act on this system in order to identify agents that may act on the contractile system or those control systems that are still functional in the "skinned" preparation.