Afzal N, Pierce G N, Elimban V, Beamish R E, Dhalla N S
Division of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, Canada.
Am J Physiol. 1989 Apr;256(4 Pt 1):E453-8. doi: 10.1152/ajpendo.1989.256.4.E453.
The effects of verapamil on cardiac myofibrillar adenosinetriphosphatase (ATPase) activity, myosin ATPase, and myosin isoenzyme profile as well as sarcoplasmic reticular Ca2+ uptake and ATPase activities were examined in Sprague-Dawley rats made diabetic with a single injection of streptozotocin (65 mg/kg). Myofibrillar ATPase activity and myosin Ca2+ ATPase activity as well as Ca2+ uptake and Ca2+-stimulated ATPase activities of the sarcoplasmic reticulum were significantly decreased in diabetic hearts in comparison to the control values. The myosin isoenzyme component V3 was prominent in diabetic hearts, whereas V1 isoenzyme was the major myosin component in control hearts. Chronic treatment of diabetic rats with verapamil (8 mg/kg daily for 4-8 wk) resulted in an improvement of the altered myofibrillar ATPase activity, myosin ATPase, myosin isoenzyme distribution, and sarcoplasmic reticular Ca2+-pump activities in ventricular tissue. The ability of verapamil to normalize the observed defects in the subcellular organelles in diabetic cardiomyopathy may be related to its effects in controlling the entry of Ca2+ into the cardiac cell.
在经单次注射链脲佐菌素（65毫克/千克）诱导糖尿病的斯普拉格-道利大鼠中，研究了维拉帕米对心肌肌原纤维腺苷三磷酸酶（ATP酶）活性、肌球蛋白ATP酶、肌球蛋白同工酶谱以及肌浆网Ca2+摄取和ATP酶活性的影响。与对照值相比，糖尿病心脏中的肌原纤维ATP酶活性、肌球蛋白Ca2+ ATP酶活性以及肌浆网的Ca2+摄取和Ca2+刺激的ATP酶活性均显著降低。肌球蛋白同工酶组分V3在糖尿病心脏中占主导地位，而V1同工酶是对照心脏中的主要肌球蛋白组分。用维拉帕米对糖尿病大鼠进行长期治疗（每日8毫克/千克，持续4 - 8周）可改善心室组织中改变的肌原纤维ATP酶活性、肌球蛋白ATP酶、肌球蛋白同工酶分布以及肌浆网Ca2+泵活性。维拉帕米使糖尿病心肌病亚细胞器中观察到的缺陷正常化的能力可能与其控制Ca2+进入心肌细胞的作用有关。
