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

该项目研究了老年人和老年人的线粒体功能， 线粒体能量传导减少的病理状态 可能危及组织存活。 今年我们重点关注线粒体 糖尿病大鼠的心脏功能， 链脲佐菌素，并在慢性阶段（治疗后6-8周）进行研究 疾病。 从糖尿病动物心脏分离的线粒体， 显示出对底物（谷氨酸）氧化能力不变 加上苹果酸盐）和不变的呼吸控制比率。 直接测量 线粒体膜钙离子梯度（[Ca 2 +]m/[Ca 2 +]o） indo-1负载的线粒体在糖尿病患者和 对照动物。 然而，线粒体游离Ca 2+浓度的研究 [Ca2+]m，在单个分离的心肌细胞中原位，使用荧光 LCS中开发的显微镜技术显示，[Ca 2 +]m升高较少， 糖尿病动物对电刺激的反应比年龄大， 匹配的控制。 [Ca ~（2+）]m峰值分别为0.30 q、0.02 fM和0.45 q 0.02糖尿病动物和对照动物的fM：差异为 显著（p<0.05）。 然而，静息、非刺激的[Ca 2 +]m 在糖尿病动物的细胞中较高（0.13 q 0.01 fM vs 0.07 q 0.01分别为糖尿病患者和对照组的fM）。 这些结果一起 表明在这种模式下兴奋-收缩偶联机制的损伤 糖尿病性心肌病-一个可以直接测试的建议， 细胞质游离Ca 2+的测量。 [Ca ~（2+）]m未能上升到As 在很大程度上刺激了糖尿病动物的肌细胞 可能是丙酮酸氧化激活失败的原因， 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.