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Effects of anesthetics on ATPase activlty and motility of adomyosin dirrectly studied by in vitro motility assay.

通过体外运动测定直接研究麻醉剂对 ATP 酶活性和阿多肌球蛋白运动的影响。

基本信息

批准号：
07671658
负责人：
MASHIMO Takashi
金额：
$ 1.41万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07671658/
关键词：
actomyosin actin motility ATPase local anesthetic lidocaine tetracaine

项目摘要

Using a recently developed in vitro motility assay, we have demonstrated that local anesthetics, lidocaine and tetracaine directly inhibit myosin-based movement of single actin filaments in a reversible dose-dependent manner. The inhibitory action of the local anesthetics on actomyosin sliding movement was pH dependent ; the anesthetics were more potent at higher pH values, and this reaction was accompanied by an increased proportion of the uncharged form of the anesthetics. QX-314, a permanently charged derivative of lidocaine, had no effect on actomyosin sliding movement. These results indicate that the uncharged form of local anesthetics is predominatly responsible for the inhibition of actomyosin sliding movement. The local anesthetic inhibited aliding movement but hardly interfered with the binding of actin filaments to myosin on the surface or with actomyosin ATPase activity at low ionic strength. To characterize the actomyosin interaction in the presence of anesthetics, we measured the binding and breaking force of the actomyosin complex. The binding of actin filaments to myosin on the surface was not affected by lidocaine at low ionic strength. The results suggest that the binding and ATPase of actomyosin are governed predominantly by ionic interaction, which is hardly affected by anesthetics ; whereas the force generation requires hydrophobic interaction, which plays a major part of the strong binding and is blocked by anesthetics, in addition to the ionic interaction.

使用最近发展的体外运动试验，我们已经证明了局麻药、利多卡因和丁卡因以可逆的剂量依赖的方式直接抑制基于肌球蛋白的单个肌动蛋白细丝的运动。局麻药对肌动球蛋白滑动运动的抑制作用具有pH依赖性，pH值越高，抑制作用越强，且这种反应伴随着非荷电形式比例的增加。QX-314是一种永久带电的利多卡因衍生物，对肌动球蛋白的滑动运动没有影响。这些结果表明，局麻药的不带电形式是抑制肌动球蛋白滑动运动的主要原因。局麻药抑制肌动蛋白运动，但几乎不影响肌动蛋白细丝与肌球蛋白的结合，也不影响肌动球蛋白ATPase在低离子强度时的活性。为了研究肌动球蛋白在麻醉剂存在时的相互作用，我们测量了肌动球蛋白复合体的结合力和断裂力。在低离子强度下，肌动蛋白细丝与肌球蛋白的结合不受利多卡因影响。结果表明，肌动球蛋白的结合和ATPase主要由离子相互作用控制，麻醉剂几乎不影响这种作用；而力的产生除了离子相互作用外，还需要疏水相互作用，这是强结合的主要部分，并被麻醉剂阻断。