[Use of flow cytometry to determine Ca2+ content in mitochondria and influence of calmodulin antagonists on it].

Ca ions accumulation in isolated myometrium mitochondria was investigated using flow cytometry and fluorescent probe fluo 3-AM. The addition of 1 mM of Ca2+ and 5 microM of A23187 to the incubation medium resulted in the shift to the right of geometrical peak position of fluorescence probe intensity compared with that registered in the absence of Ca ions. The increase of Ca concentration in the medium resulted in the increase of fluorescence intensity. In the conditions of Ca(2+)-uniporter functioning modelling the probe fluorescence intensity also increased depending on an increase of Ca concentration and did not change at primary presence of the 1 microM CCCP. Ca2+ accumulation in mitochondria was completely inhibited by 10 microM calmidazolium or 100 microM trifluoperazine, known as calmodulin antagonists. It was also shown that these calmodulin antagonists caused mitochondria membrane depolarization. The membrane potential was measured using fluorescent probe TMRM. It is supposed that the inhibitory action of calmodulin antagonists on Ca ions accumulation in myometrium mitochondria can occur due to direct inhibition of Ca(2+)-uniporter and/or due to membrane potential dissipation.