[Studies of Ca2+ -dependent smooth muscle mitochondria swelling using flow cytometry and spermine effects on this...

In the experiments, which were carried out using flow cytometry on isolated uterus mitochondria of nonpregnant rats, conditions for studying Ca2+-induced increase in nonspecific permeability of mitochondial membrane were tested. Fluorescent probe nonyl acridin orange was used to determine the purity of isolated mitochondria. Mitochondrial swelling induced by addition of Ca2+ or alamethicin was detected as a decrease in light side scattering (SS). It was shown that mitochondrial swelling in the presence of 100 microM Ca plus 1 microM A23187 was 86 +/- 4% compared with maximal response after alamethicin treatment. The calcium-induced swelling of mitochondria was inhibited by the addition of 5 microM cyclosporin plus 40 microM ADP. Mitochondrial swelling was inhibited by spermine at a dose of 0.1 micromol/mg or induced at a dose of 10 micromol/mg. It was supposed that the experimental approach proposed in this paper can be useful for mitochondrial pore modulating effectors screening.