Afzal N, Dhalla N S
Division of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, Manitoba, Canada.
Am J Physiol. 1992 Mar;262(3 Pt 2):H868-74. doi: 10.1152/ajpheart.1992.262.3.H868.
To examine the status of sarcoplasmic reticulum (SR) with respect to Ca2+ transport in congestive heart failure due to myocardial infarction, the left coronary artery in rats was ligated for 4, 8, and 16 wk. The left heart function was assessed with an intraventricular pressure transducer, and SR membrane fractions from the right ventricle and the viable left ventricle were isolated for measuring the ATP-dependent Ca2+ uptake activities. In comparison to sham-operated controls, SR Ca2+ uptake activity was decreased in viable left ventricle of the experimental animals at 4, 8, and 16 wk. On the other hand, SR Ca2+ uptake activity in the right ventricle was increased at 4 and 8 wk, but no change was apparent at 16 wk of coronary occlusion. The decrease in SR Ca2+ uptake in left ventricle and increase in right ventricle were associated with corresponding changes in maximal velocity values without any alterations in the affinity for Ca2+. These opposite changes in the right and left ventricles were dependent on the scar size as well as time after inducing the myocardial infarction. The SR Ca(2+)-stimulated adenosinetriphosphatase activity was decreased in left ventricle and increased in the right ventricle from 4 wk experimental animals. The results suggest differential remodeling of the SR membranes with respect to Ca(2+)-pump mechanisms in left and right ventricles during the development of congestive heart failure.
为了研究心肌梗死所致充血性心力衰竭时肌浆网（SR）的钙离子转运状况，将大鼠的左冠状动脉结扎4周、8周和16周。用室内压力传感器评估左心功能，并分离右心室和存活左心室的SR膜组分，以测量ATP依赖的钙离子摄取活性。与假手术对照组相比，实验动物存活左心室的SR钙离子摄取活性在4周、8周和16周时均降低。另一方面，右心室的SR钙离子摄取活性在4周和8周时增加，但在冠状动脉闭塞16周时无明显变化。左心室SR钙离子摄取的减少和右心室的增加与最大速度值的相应变化相关，而对钙离子的亲和力没有任何改变。左右心室的这些相反变化取决于梗死面积以及心肌梗死后的时间。4周龄实验动物的左心室SR钙离子刺激的三磷酸腺苷酶活性降低，右心室增加。结果表明，在充血性心力衰竭发展过程中，左右心室SR膜在钙离子泵机制方面存在差异性重塑。
