Mitochondrial Reticulum of Skeletal Muscles. Proven and Hypothetical Functions

In the 70s and 80s of the last century, the presence of the mitochondrial reticulum in skeletal muscles has been outlined. The concept functioning this reticulum in a cell to deliver energy throughout the cell volume in the form of a transmembrane potential built on the inner membrane of mitochondria, followed by the synthesis of ATP by mitochondrial ATP synthase, was put forth and proved. However, evidence based on studies of mitochondrial ultrastructure remains subject to criticism. To exclude the possibility of artifacts caused by the preparation of the sample for electron microscopy, the mitochondrial structure detected in ultrathin sections of muscle fiber used in electron microscopy and the structure in intact fiber were compared with the visualization of mitochondria with a membrane potential- dependent dye. This comparison was carried out for two species: mice and the naked mole rat, known for its extraordinary longevity. Full compliance with the previously made conclusions about the structure of the mitochondrial reticulum has been obtained. An additional model of the functioning of giant mitochondria as intracellular structures that prevent hypoxia in tissues is proposed.