Ca^<2+> TRANSIENTS AND CELL SHORTENING IN DIABETIC RAT VENTRICULAR MYOCYTES

概要

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To investigate the role of abnormal Ca^<2+> metabolism in the diminished contractile function of diabetic myocardium, we measured the Ca^<2+> transients and cell contraction of diabetic rat myocytes. Isolated diabetic (8 weeks after 40 mg/kg streptozotocin, i.v.) and normal myocytes were loaded with acetoxymethyl ester of indo-1 (indo-1/AM). Ca^<2+> transients and cell circumferential shortening were measured simultaneously, using high temporal resolution video image analysis. The diastolic base and systolic peak of Ca^<2+> transients were significantly lower in diabetic myocytes than in normal myocytes (peak ratios: 0.49±0.02 vs 0.56±0.01, p<0.05; base ratios: 0.43±0.01 vs 0.48±0.01, p<0.01, Mea±SE). The cell circumferential shortening of diabetic myocytes was also significantly lower than that of normal myocytes (2.9±0.3% vs 5.2±0.9%, p<0.05). Although isoproterenol (10-8 and 10-7 M) increased the peak of Ca^<2+> transients in both diabetic and normal myocytes, the peak value of Ca^<2+> transients in the diabetic group was significantly lower than that in the normal group. The decreased Ca^<2+> transients may be responsible for the decreased contractile function in diabetic myocardium.
社団法人日本循環器学会の論文
1993-05-20