Potassium-chloride promiscuous channels in mitochondrial membranes.
Mitochondrial membranes isolated from a rat heart muscle were incorporated into a bilayer lipid membrane (BLM) and channel currents were measured in 250/50 mmol/l KCl cis/trans solutions. The channel currents measured from -40 to +40 mV had various linear voltage-current relationships and K(+)/Cl(-) permeability ratios at distinct voltage ranges. The channels possessed K(+)-Cl(-) promiscuous property. Depending on voltage, membrane permeability suddenly switched from K(+) over Cl(-) to Cl(-) over K(+) and back. The channels had Cl(-)/K(+) > 1 permeability at potentials around 0 mV and the permeability was switched to K(+)/Cl(-) > 1 at more negative and positive potentials. The chloride channel blocker, 5-nitro-2-(phenylpropylamino)-benzoate (NPPB, 5 x 10(-5) mol/l), influenced properties of the promiscuous channels - it activated potassium conductance of the channels.
Ondrias
K
K
Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlárska 5, 833 34 Bratislava, Slovakia. karol.ondrias@savba.sk
Malekova
L
L
Krizanova
O
O
D000818:Animals; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D066298:In Vitro Techniques; D008051:Lipid Bilayers / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000187:drug effects / Q000378:metabolism*; D009579:Nitrobenzoates / Q000494:pharmacology; D015221:Potassium Channels / Q000378:metabolism*; D051381:Rats; D050994:Voltage-Dependent Anion Channels / Q000378:metabolism
D018118:Chloride Channels; D008051:Lipid Bilayers; D009579:Nitrobenzoates; D015221:Potassium Channels; D050994:Voltage-Dependent Anion Channels; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid