Tag Archives: myometrium
Activation of glybenclamide-sensitive mitochondrial swelling under induction of cyclosporin of A-sensitive mitochondrial pore
O. B. Vadzyuk, S. A. Kosterin
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: olga_vadzyuk@hotmail.com
Induction of mitochondrial swelling and increased generation of reactive oxygen forms by Ca ions have been shown in suspension of mitochondria from rat uterus. These effects were suppressed by the blocker of mitochondrial Ca2+-uniporter ruthenium red and MPTP inhibitor сyclosporin A, that evidences that the induction of mitochondrial permeability transition pore by Ca ions takes place. Ca2+-induced mitochondrial swelling was blocked by ATP-sensitive channel blocker glybenclamide but only if K+ was present in the incubation medium. We also demonstrated that Ca2+-induced mitochondrial swelling can be eliminated in the presence of ROS scavengers N-acetyl cysteine and ascorbate. This effect of scavengers was also sensitive to K+ and was not revealed in the medium that contained equimolar NaCl instead of KCl. Thus, our data gave us grounds to assume that the induction of MPTP by Ca ions evokes the activation of mitochondrial ATP-sensitive K+-channels, which are mediated by ROS.
Ca(2+)/H(+)-exchange in myometrium mitochondria
O. V. Kolomiets, Yu. V. Danylovych, H. V. Danylovych, S. O. Kosterin
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: danylovych@biochem.kiev.ua
Using the fluorescent probe Fluo-4 AM the authors have identified Na+-independent Ca2+/H+-exchange in isolated mitochondria of rat myometrium and studied its individual properties. Formation of directional protons gradient in the matrix of mitochondria causes antyporte release of Ca2+, which has been previously accumulated in energetic processes (in the presence of Mg-ATP and succinate). The functioning of Ca2+/H+-exchange depends on the proton gradient and is characterized by reversibility, in case of extramitochondria environment alkalization the additional accumulation of Ca2+ by organelles is recorded. Monovalent cations gradients (Na+, K+, Li+) do not cause the release of Ca2+ from mitochondria. Rate of Ca2+/H+-exchange is growing in terms of increasing ΔpH on the mitochondria membrane and kinetics of ΔpH-induced Ca2+ release from the matrix corresponds to the laws of first order reaction. Research of Ca2+/H+-exchange some properties in the myometrium mitochondria showed that the above transport process is of electrogenic nature, perhaps it is done in a 1 : 1 stechiometry (Hill coefficient on H+ close to 1) and is able to adjust matrix Ca2+ concentration under physiological conditions (pH activation of about 6.9). Thus, in the inner membrane of the myometrium mitochondria the available system of the secondary active Ca2+-transport from the matrix of these organelles to myoplasm and the functioning of Ca2+/H+-exchanger may underlie this process.
Investigation of nitrosactive compounds influence on polarization of the mitochondrial inner membrane in the rat uterus myocytes using potential sensitive fluorescent probe DіOC(6)(3)
Yu. V. Danylovych, H. V. Danylovych, O. V. Kolomiets, S. O. Kosterin, S. A. Karakhim, A. Yu. Chunikhin
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: danylovych@biochem.kiev.ua
The effect of nitrosactive compounds (sodium nitroprusside and sodium nitrite) on the polarization level of the uterus myocytes inner mitochondrial membrane using the confocal laser microscopy and fluorescent probe potentialsensitive DiOC6(3) (3,3′-dihexyloxacarbocyanine) was ivestigated. Colocalisation of mitochondrial membranes specific fluorescent probes (MitoTracker Orange CM H2TMRos, 10 – nonyl acridine orange and DiOC6(3)) was demonstrated. It was shown that sodium nitroprusside at 0.1 mM concentration caused a moderate decrease in mitochondrial transmembrane potential. That observation was confirmed by flow cytometry. Action efficiency of sodium nitrite in a similar concentration was significantly lower than that of sodium nitroprusside. It is shown that it was sodium nitroprusside which caused a slight swelling of the mitochondria. A possible protecting role of nitric oxide as to mitochondria was discussed.