REGULATION OF ENERGY METABOLISM IN AGING AND DISEASE--CARDIOVASCULAR SYSTEM

这个项目研究了线粒体在老年和老年中的功能。 线粒体能量转导减少的病理状态 可能会影响组织的存活。我们今年的重点是线粒体 对糖尿病大鼠心脏功能的影响 链脲佐菌素在慢性期(治疗后6-8周)的研究 这种疾病的危害。从糖尿病动物心脏分离的线粒体 显示出对底物(谷氨酸)的氧化能力不变 加上苹果酸)和不变的呼吸控制比率。直接测量 线粒体膜上的钙梯度([Ca~(2+)]m/[Ca~(2+)]o) 与Indo-1负载的线粒体相比，糖尿病和糖尿病患者之间没有差异 控制动物。然而，线粒体游离钙离子浓度的研究 [Ca~(2+)]m，在单个、分离的心肌细胞中，使用荧光 LCS发展的显微技术显示，[Ca2+]m上升较少 对糖尿病动物的电刺激的反应比年龄更大- 配对的对照组。[Ca~(2+)]_m峰值分别为0.30Q、0.02fM和0.45Q 糖尿病动物和对照动物的Fm分别为0.02Fm：差异为 显著(p&lt；0.05)。然而，静息、非刺激性[Ca~(2+)]_m 在糖尿病动物细胞中的含量较高(0.13Q0.01Fm比0.07Qvs0.07Q. 糖尿病组和对照组分别为0.01Fm)。总而言之，这些结果 提示在这种模式下兴奋-收缩偶联机制存在损伤 糖尿病心肌病--这一建议可以直接通过 胞浆游离钙离子的测定。[Ca~(2+)]_m未能升至AS 对糖尿病动物心肌细胞的刺激作用 可能是未能激活丙酮酸氧化的基础，如所述 其他地方。

This project examines mitochondrial functioning in old age and in pathological states in which decreased energy transduction by mitochondria may compromise tissue survival. We have focused this year on mitochondrial functioning in the hearts of rats made diabetic by treatment with streptozotocin and studied in the chronic stage (6-8 weeks after treatment) of the disease. Mitochondria isolated from hearts of diabetic animals were shown to exhibit an unchanged capacity for oxidation of substrate (glutamat plus malate) and unchanged respiratory control ratios. Direct measurement of the Ca2+ gradient across the mitochondrial membrane ([Ca2+]m/[Ca2+]o) with indo-1-loaded mitochondria showed no difference between diabetic and control animals. However, studies of mitochondrial free Ca2+ concentration [Ca2+]m, in situ in single, isolated cardiac myocytes, using a fluorescence microscopy technique developed in LCS, showed that [Ca2+]m rises less in response to electrical stimulation from diabetic animals than from age- matched controls. Peak values of [Ca2+]m were 0.30 q 0.02 fM and 0.45 q 0.02 fM for diabetic and control animals respectively: the difference is significant (p<0.05). However, values of resting, non-stimulated [Ca2+]m were higher in cells from the diabetic animals (0.13 q 0.01 fM vs 0.07 q 0.01 fM for diabetic and control, respectively). Together, these results suggest a lesion in excitation-contraction coupling mechanisms in this mode of diabetic cardiomyopathy - a proposal that could be tested directly by measurements of cytosol free Ca2+. The failure of [Ca2+]m to rise to as great an extent on stimulation of the myocytes from the diabetic animal could underlie the failure to activate pyruvate oxidation, as described elsewhere.