Loupatatzis 2002 Cell Physiol Biochem

Loupatatzis C, Seitz G, Schoenfeld P, Lang F, Siemen D (2002) Single-channel currents of the permeability transition pore from the inner mitochondrial membrane of rat liver and of a human hepatoma cell line. Cell Physiol Biochem 12: 269-278.

Loupatatzis C, Seitz G, Schoenfeld P, Lang F, Siemen D (2002) Cell Physiol. Biochem.

Abstract: Single-channel currents were recorded from inner mitochondrial membranes of HepG2 hepatoma cells and of normal rat liver cells by means of patch-clamp techniques. The current events showed variable amplitudes of up to 1.1 ± 0.2 nS (n = 35) at room temperature (24 °C) and of up to 1.5 ± 0.2 nS (n = 10) at 34 °C including large numbers of subconductance states. Voltages of -40 mV and below closed the channels usually with a delay of about 2 min. Increasing Ca²⁺ concentrations activated the channels, whereas cyclosporin A (100 nM) blocked. The concentration-response relation for the Ca²⁺-effect could be fitted best using an EC50 of 10 μM and a Hill coefficient of 1.5. Taken together the results indicate that we recorded from the permeability transition pore (PTP). As PTP activity may be related to apoptosis we tested if lysate from differently treated T-lymphocytes (Jurkat cells) was able to induce PTP activity in HepG2 cells. Lysate of untreated cells completely abolished the activity at a Ca²⁺ oncentration of 18 nM (buffered by EGTA), i.e. three orders of magnitude below the EC50. Under these conditions the lysate is not likely to contain stable factors that could open the PTP. Preliminary experiments show PTP activity in CD95-activated lysate.

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Organism: Rat  Tissue;cell: Hepatocyte; Liver"Hepatocyte; Liver" is not in the list (Heart, Skeletal muscle, Nervous system, Liver, Kidney, Lung;gill, Islet cell;pancreas;thymus, Endothelial;epithelial;mesothelial cell, Blood cells, Fat, ...) of allowed values for the "Tissue and cell" property.  Preparation: Isolated Mitochondria"Isolated Mitochondria" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property. 

Regulation: Coupling; Membrane Potential"Coupling; Membrane Potential" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property. 

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