Sustained oscillations of transmembrane Ca2+ fluxes in mitochondria and their possible biological significance

Sustained oscillations of transmembrane fluxes of Ca2+ and other ions in is olated mitochondria are described. The data are presented that the major ca use of the oscillations is the Ca2+-induced Ca2+-efflux from the mitochondr ial matrix and spontaneous opening/closing of the permeability transition p ore in the inner mitochondrial membrane. Conditions favourable for the gene ration of oscillations are considered. The role of phospholipid peroxidatio n and hydrolysis in the generation of [Ca2+] oscillations is emphasized. Literature data concerning [Ca2+] changes in the mitochondrial matrix in in tact cells and the data on the participation of mitochondria in intracellul ar Ca2+ oscillation and in the Ca2+ wale propagation are reviewed. The hypo thesis that mitochondria are able to generate [Ca2+] oscillations in intact cells is put forward. It is assumed that Ca2+ oscillations can protect mit ochondria of resting cells from osmotic shock and oxidative stress.