Isolated rat liver mitochondria were proposed as a model to monitor real-time heat metabolism. A high-throughput and sensitive thermal activity monitor III (TAM III) was used to detect the P-t curves of mitochondria under different conditions, including different mitochondrial concentrations, different substrates, different buffers,respiratory inhibitors, Ca2+, and CsA. We determined the thermokinetic parameters through calculation. The results showed that: (1) higher concentration of mitochondria led to faster energetic metabolism; (2) when succinate was the direct respiratory substrate, it promoted mitochondrial metabolism, in contrast to the condition when an indirect substrate,pyruvate, was used; (3) high concentration of Ca2+ (2.5 mmol·L-1) stimulated mitochondrial metabolism, however CsA, an inhibitor of mitochondrial permeability transition pores, could not reverse the Ca2+-induced mitochondrial alteration; (4)mitochondria in various buffers displayed different rates of heat metabolism, because of the different composition of the buffers; (5) mitochondrial metabolism was inhibited by respiratory inhibitors, especially NaN3, which is an inhibitor of Complex IV and which completely stopped the mitochondrial heat release.%为了探究线粒体的能量代谢过程,本文以离体大鼠肝脏线粒体为模型,利用多通道、高灵敏度的热活性检测仪TAMⅢ,实时监测了不同线粒体浓度、不同底物、不同缓冲液、几种呼吸抑制剂以及Ca2+和线粒体渗透转换孔抑制剂CsA存在时线粒体的能量代谢,获得了完整的热功率―时间曲线,并通过计算得到了线粒体能量代谢的热动力学参数.通过分析发现:(1)线粒体浓度越大,代谢越快;(2)直接底物琥珀酸钠使线粒体代谢更快;(3)高浓度Ca2+能够刺激线粒体快速产热,且在长期代谢进程中,线粒体渗透转换孔抑制剂CsA并不能改变Ca2+造成的影响;(4)不同缓冲液对线粒体代谢的影响基于其组分的不同,缓冲液中含有呼吸底物;(5)呼吸抑制剂都能抑制线粒体的能量代谢,尤其是复合物Ⅳ的抑制剂NaN3,高浓度下使代谢停止.
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