Effects of a mechanical loading on the actomyosin kinetics and the fiber-pherotypes of masticatory muscles.

机械负荷对肌动球蛋白动力学和咀嚼肌纤维表型的影响。

基本信息

批准号：
07457443
负责人：
SAEKI Yasutake
金额：
$ 4.67万
依托单位：
Tsurumi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07457443/
关键词：
guinea pig bite-opening in vitro motility assay ATPase activity myosin heavy chain myosin light chain tropomyosin masseter muscle ラットアクチン滑り速度咀嚼筋ミオシンアイソフォーム電気泳動

项目摘要

To study the effects of increased occlusal vertical dimension on (1) the actomyosin kinetics and (2) the fiber-phenotypes of masticatory muscles, we analyzed the sliding velocity of actin filaments on myosins (by an in vitro motility assay), the myosin ATPase activity and the contractile protein compositions in masseter muscles obtained from normal (control) and bite-opened (5.7 mm increase in the vertical dimension for 1 week) guinea pigs.1. Effects of bite-opening on the actomyosin kinetics.In control myosin preparations, the actin-filament sliding velocity at 25ﾟC was 4.0(]SY.+-。[)0.3mum/s (mean(]SY.+-。[)SD, n=5). In bite-opened myosin preparations (n=5), it was 3.4(]SY.+-。[)0.3mum/s, a significant (rho<0.01) decrease. Myosin ATPase activity was also decreased significantly (rho<0.01) from 1.0(]SY.+-。[)0.1 to 0.7(]SY.+-。[)0.1 mumol Pi/mg/min (mean(]SY.+-。[)SD,n=5) after the bite-opening treatment. These results suggest that the 1-week bite-opening treatment decreases the turnover ra … More te of actin-myosin interaction in the masseter.2. Effects of bite-opening on the fiber-phenotypes.Compositions of myosin heavy chain (MHC), myosin light chain (MLC) and tropomyosin were investigated by gel electrophoresis in conjunction with densitometric analysis. Masseter muscle contained two fast-type MHC isoforms, MHC IIa and IId (or IIx). Averaged densitometric data (n=4) indicated no significant (rho>0.05) change in MHC composition between the two groups. Although the MLC consisted of three components, LC1f, LC2f and LC3f, a significant (rho<0.01) increase in the relative content of LC1f at the expense of that of LC3f was observed after the bite-opening treatment. Although the tropomyosin consisted of two components, TM-alpha and TM-beta, a significant (rho<0.05) increase in the relative content of TM-beta as well as a significant (rho<0.05) decrease in that of TM-alpha were observed in association with the bite-opening treatment.These results suggest that in guinea pigs the 1-week bite-opening treatment changes the actomyosin kinetics as well as the compositions of MLC and tropomyosin to meet altered functional demands. Less

为了研究增加咬合垂直尺寸对（1）咀嚼肌肉的肌动蛋白动力学和（2）咀嚼肌的纤维表型的影响，我们分析了肌动蛋白对肌动蛋白上肌动蛋白丝的滑动速度（通过体外运动分析），肌动蛋白的蛋白质蛋白质表相位群体中的肌动蛋白的效果（通过体外运动）中的速度（（垂直尺寸增加1周的5.7毫米）豚鼠1。咬合对肌动蛋白动力学的影响。在控制肌球蛋白制剂中，肌动蛋白丝滑动速度在25°C时为4.0（]SY。+ - 。[）0.3MUM/S（平均值（]SY。+ - 。。[）SD，n = 5）。在咬伤的肌球蛋白制剂（n = 5）中，它为3.4（]SY。+ - 。[）0.3MUM/s，显着（Rho <0.01）降低。肌球蛋白ATPase活性也显着降低（RHO <0.01）从1.0（]SY。+ - 。[）0.1至0.7（]SY。+ - 。[）0.1 MUMOL PI/mg/min（平均（平均（]SY。+ - 。[）SD，n = 5）。这些结果表明，1周的咬合治疗降低了肌肉运动中肌动蛋白 - 肌球蛋白相互作用更多的营业额。2。咬合对肌球蛋白重链（MHC），肌球蛋白轻链（MLC）（MLC）和tropomyosin的纤维型对纤维型的影响与密度分析一起投资。咬肌包含两个快速类型的MHC同工型，MHC IIA和IID（或IIX）。平均光密度数据（n = 4）表明两组之间MHC组成没有显着变化（RHO> 0.05）。尽管MLC由三个成分组成，即LC1F，LC2F和LC3F，但在开放式处理后观察到LC1F的相对含量显着增加（RHO <0.01），而LC1F的相对含量则以牺牲LC3F为代价。尽管肌球蛋白由两个成分TM-Alpha和TM-Beta组成，但观察到TM-beta的相对含量显着增加（RHO <0.05），以及与咬伤治疗相关的TM-Alpha的显着（Rho <0.05）降低。这些结果表明，在豚鼠中，1周的咬合咬合治疗改变了肌动球蛋白动力学以及MLC和Tropomyosin的组成，以满足功能的改变。