MYOCARDIAL RESPONSE TO EXERCISE DURING SENESCENCE

拟议工作的总体目标是确定 在衰老期间进行耐力运动将逆转衰老相关的下降 在心肌细胞的特性，从而导致一个 改善心肌功能。 另一些人认为， 肌浆网的功能可能是一个重要因素， 减缓心肌等长收缩持续时间， 衰老 此外，心肌蛋白质合成明显减少， 有机体从成熟到衰老。 因此，本提案涉及 通过检查肌浆网和蛋白质合成， 在成年和衰老大鼠的心脏中的更详细的信息， 测定这两个参数对耐力的反应性 锻炼的 心肌细胞ATP依赖性钙转运特性 将使用生化和形态学检查肌浆网 技术，以确定（1）钙通量有关的水解 在各种条件下的ATP和（2）钙的密度 转运ATP酶，在原位和体外。 心肌梗死发生率 蛋白质合成将估计肌动蛋白，细胞色素c，和核糖体 proteins. 肌动蛋白和细胞色素c的mRNA水平将是 测定了 肌浆网和蛋白质合成都将 在特定时间段的耐力运动训练前后进行检查 在衰老过程中。 离体心脏的等长收缩参数 将在运动训练的每个时间点评估乳头肌 以确定心肌功能是否有所改善。 这些 因此，研究将确定细胞因子的适应性， 衰老过程中心肌耐力运动与 心肌功能 通过这种方式， 参与衰老期间锻炼的有益方面可能是 获得。

The overall aim of the proposed work is to determine whether or not endurance exercise during senescence will reverse the aging-related decline in the cellular properties of the myocardium, thereby leading to an improved myocardial function. Others have suggested that the decreased function of the sarcoplasmic reticulum may be an important factor in the slowing of the isometric contractile duration of cardiac muscle with aging. Moreover, myocardial protein synthesis apparently decreases as the organism ages from maturity to senescence. Therefore, this proposal deals with the examination of the sarcoplasmic reticulum and protein synthesis in greater detail in the hearts of adult and senescent rats followed by the determination of the responsiveness of these two parameters to endurance exercise. The ATP-dependent calcium transport properties of cardiac sarcoplasmic reticulum will be examined using biochemical and morphological techniques to determine (1) calcium flux in relation to the hydrolysis of ATP under a variety of conditions and (2) the density of the calcium transport ATPase, both in situ and in vitro. The rates of myocardial protein synthesis will be estimated for actin, cytochrome c, and ribosomal proteins. The levels of mRNA for both actin and cytochrome c will be measured. Both the sarcoplasmic reticulum and protein synthesis will be examined before and after specified periods of endurance exercise training during senescence. The isometric contractile parameters of isolated papillary muscle will be assessed at each time point of exercise training in order to determine any improvements in myocardial function. These studies will therefore determine the adaptability of cellular factors of the myocardium endurance exercise during senescence in relation to myocardial function. In this manner an insight into those mechanisms involved in the benefitual aspects of exercise during senescence may be gained.