Strontium and Animal Mitochondria: The Interaction of Strontium Ions with Mitochondria in Animal Tissues

Abstract

At the beginning of the 1960s it was discovered that, in addition to oxidative phosphorylation, one of the energy-linked reactions that takes place in mitochondria is the accumulation of Ca2+ ions (1–3). Further investigation demonstrated the ability of isolated mitochondria to accumulate significant quantities of Sr2+ (4–9), Mn2+ (10–12), Ba2+ (6,12), and, in the case of mitochondria of the heart, Mg2+ ions as well (13). Because uncoupling agents and respiratory inhibitors affect the transport of divalent cations to the same extent as they affect oxidative phosphorylation, it was concluded that both processes are maintained by a single unit or a single condition that is generated in the mitochondria (2,14). As a result of investigations carried out in several laboratories (2,15–17), it was shown that the mitochondrial transport of divalent cations may be described within the framework of Mitchell’s chemiosmotic theory: the accumulated ions are distributed according to the electrochemical potential generated in the internal membrane by the respiratory chain or in H+-ATPase. In any case, the elucidation of particulars of the transport of divalent cations has assisted in developing the current concept of the mechanism by which energy is transformed in the mitochondria.