Caloric restriction (CR) is widely known to increase life span and resistance to different types of injuries in several organisms. We have previously shown that mitochondria from livers or brains of CR animals exhibit higher calcium uptake rates and lower sensitivity to calcium-induced mitochondrial permeability transition (mPT), an event related to the resilient phenotype exhibited by these organs. Given the importance of calcium in metabolic control and cell homeostasis, we aimed here to uncover possible changes in mitochondrial calcium handling, redox balance and bioenergetics in cardiac and skeletal muscle mitochondria in response to six months of CR. Unexpectedly, we found that CR does not alter the susceptibility to mPT in muscle (cardiac or skeletal), nor calcium uptake rates. Despite the lack in changes in calcium transport properties, CR consistently decreased respiration in the presence of ATP synthesis in heart and soleus muscle. In heart, such changes were accompanied by a decrease in respiration in the absence of ATP synthesis, lower maximal respiratory rates and a reduced rate of hydrogen peroxide release. Hydrogen peroxide release was unaltered by CR in skeletal muscle. No changes were observed in inner membrane potentials and respiratory control ratios. Together, these results highlight the tissue-specific bioenergetic and ion transport effects induced by CR, demonstrating that resilience against calcium-induced mPT is not present in all tissues.

热量限制（CR）可以延长寿命，并能抵抗多种生物体对不同类型伤害的抵抗力。先前我们已经表明，来自CR动物的肝脏或大脑的线粒体表现出较高的钙摄取率，并且对钙诱导的线粒体通透性转变（mPT）的敏感性较低，这是与这些器官表现出的弹性表型有关的事件。考虑到钙在代谢控制和细胞稳态中的重要性，我们的目的是揭示响应六个月的CR后线粒体钙处理，氧化还原平衡以及心脏和骨骼肌线粒体中生物能的可能变化。出乎意料的是，我们发现CR不会改变肌肉（心脏或骨骼）对mPT的敏感性，也不会改变钙的摄取率。尽管钙转运特性没有变化，在心脏和比目鱼肌中存在ATP合成时，CR持续降低呼吸。在心脏中，这种变化伴随着在没有ATP合成的情况下呼吸减少，最大呼吸频率降低和过氧化氢释放速率降低。骨骼肌中的CR不会改变过氧化氢的释放。内膜电位和呼吸控制率未见变化。总之，这些结果突显了CR诱导的组织特异性生物能和离子转运效应，表明并非在所有组织中都存在针对钙诱导的mPT的适应力。最大呼吸频率降低，过氧化氢释放速率降低。骨骼肌中的CR不会改变过氧化氢的释放。内膜电位和呼吸控制率未见变化。总之，这些结果突显了CR诱导的组织特异性生物能和离子转运效应，表明并非在所有组织中都存在针对钙诱导的mPT的适应力。最大呼吸频率降低，过氧化氢释放速率降低。骨骼肌中的CR不会改变过氧化氢的释放。内膜电位和呼吸控制率未见变化。总之，这些结果突显了CR诱导的组织特异性生物能和离子转运效应，表明并非在所有组织中都存在针对钙诱导的mPT的适应力。