CELLULAR ADAPTATIONS OF MYOCARDIUM TO EXERCISE TRAINING

描述（改编自申请人摘要）：参与训练诱导的心肌收缩机制适应的细胞机制尚不清楚。本研究在单个心肌细胞水平上测试了关于收缩适应的假设。将测量从运动训练的大鼠和不运动的对照组的心脏中分离出的单个心肌细胞的收缩特性。训练对等长力的钙敏感性和力的动力学特性（力发展速率和松弛速率）的影响将被确定。运动训练对最大缩短速度和心肌细胞力-速度关系的影响也将被确定。肌细胞收缩功能的改变与收缩蛋白的异构体组成及其磷酸化状态有关。

DESCRIPTION (Adapted from the applicant's abstract): The cellular mechanisms that are involved in training-induced adaptations of the contractile machinery of the myocardium are not well understood. Work in this proposal tests hypotheses regarding contractile adaptations at the level of the single cardiac myocyte. The contractile properties of single cardiac myocytes isolated from the hearts of both exercise trained rats and sedentary controls will be measured. The effect of training on the calcium sensitivity of isometric force and kinetic properties of force (rate of force development and rate of relaxation) will be determined. The effect of exercise training on the maximal shortening velocity and the force-velocity relationship of cardiac myocytes will also be determined. Changes in contractile function of the myocytes will be correlated with the isoform composition of contractile proteins and their phosphorylation state.