Farrar R P, Starnes J W, Cartee G D, Oh P Y, Sweeney H L
Department of Kinesiology, University of Texas, Austin 78712.
J Appl Physiol (1985). 1988 Feb;64(2):880-3. doi: 10.1152/jappl.1988.64.2.880.
The effects of aging and exercise on isoforms of cardiac myosin and Ca2+-activated actomyosin adenosinetriphosphatase (ATPase) activity were examined in Fischer 344 rats. Rats were divided into running (R) and age-matched sedentary (S) groups. The groups initiated their exercise program at either 3, 4, or 18 mo of age. Rats were killed at 10, 12, 24, or 27 mo of age. ATPase activity decreased 25% in the S group and 28% in the R group from 12 to 27 mo of age. The myosin isozyme patterns shifted in both S and R groups from a predominantly V1 isozyme form (63.8%) at 10 mo of age to a more equal distribution of isozyme forms at 24 mo (V1, V2, and V3 comprising 40.0, 27.8, and 31.9%, respectively). Age-related shifts in myosin composition occurred despite chronic endurance training at an intensity of approximately 75% maximum O2 consumption. Improvement of cardiac performance through training during aging is not accompanied by attenuating shifts in myosin isozyme composition.
在Fischer 344大鼠中研究了衰老和运动对心肌肌球蛋白亚型以及Ca2+激活的肌动球蛋白三磷酸腺苷酶（ATPase）活性的影响。大鼠被分为跑步（R）组和年龄匹配的久坐不动（S）组。这些组在3、4或18月龄时开始其运动计划。大鼠在10、12、24或27月龄时被处死。从12月龄到27月龄，S组的ATPase活性下降了25%，R组下降了28%。S组和R组的肌球蛋白同工酶模式均从10月龄时主要为V1同工酶形式（63.8%）转变为24月龄时同工酶形式分布更为均衡（V1、V2和V3分别占40.0%、27.8%和31.9%）。尽管进行了强度约为最大耗氧量75%的长期耐力训练，但肌球蛋白组成仍出现了与年龄相关的变化。衰老过程中通过训练改善心脏功能并未伴随着肌球蛋白同工酶组成变化的减弱。
