Skalska 2009 Int J Mol Sci

Skalska J, Bednarczyk P, Piwonska M, Kulawiak B, Wilczynski G, Dolowy K, Kudin AP, Kunz WS, Szewczyk A (2009) Calcium Ions Regulate K Uptake into Brain Mitochondria: The Evidence for a Novel Potassium Channel. Int. J. Mol. Sci. 10: 1104-1120.

» PMID: 19399240

Skalska J, Bednarczyk P, Piwonska M, Kulawiak B, Wilczynski G, Dolowy K, Kudin AP, Kunz WS, Szewczyk A (2009) Int. J. Mol. Sci.

Abstract: Abstract: The mitochondrial response to changes of cytosolic calcium concentration has a strong impact on neuronal cell metabolism and viability. We observed that Ca²⁺ additions to isolated rat brain mitochondria induced in potassium ion containing media a mitochondrial membrane potential depolarization and an accompanying increase of mitochondrial respiration. These Ca²⁺ effects can be blocked by iberiotoxin and charybdotoxin, well known inhibitors of large conductance potassium channel (BKCa channel). Furthermore, NS1619 – a BKCa channel opener – induced potassium ion–specific effects on brain mitochondria similar to those induced by Ca²⁺. These findings suggest the presence of a calcium-activated, large conductance potassium channel (sensitive to charybdotoxin and NS1619), which was confirmed by reconstitution of the mitochondrial inner membrane into planar lipid bilayers. The conductance of the reconstituted channel was 265 pS under gradient (50/450 mM KCl) conditions. Its reversal potential was equal to 50 mV, which proved that the examined channel was cation-selective. We also observed immunoreactivity of anti-β₄ subunit (of the BKCa channel) antibodies with ~26 kDa proteins of rat brain mitochondria. Immunohistochemical analysis confirmed the predominant occurrence of anti-β₄ subunit in neuronal mitochondria. We hypothesize that the mitochondrial BKCa channel represents a calcium sensor, which can contribute to neuronal signal transduction and survival. • Keywords: Mitochondria, Brain, Channel openers, Potassium channel, Iberiotoxin, NS1619.

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Organism: Rat  Tissue;cell: Neurons; Brain"Neurons; Brain" 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: Respiration; OXPHOS; ETS Capacity"Respiration; OXPHOS; ETS Capacity" 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., Ion Homeostasis"Ion Homeostasis" 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., Mitochondrial Biogenesis; Mitochondrial Density"Mitochondrial Biogenesis; Mitochondrial Density" 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. 

HRR: Oxygraph-2k