Further investigation on the high-conductance ion channel of the inner membrane of mitochondria

Sorgato, Maria Catia; Morán, Óscar; Pinto, Vito De; Keller, Bernhard U.; Stühmer, Walter

doi:10.1007/bf00762520

Cited by 52 publications

(25 citation statements)

References 41 publications

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“…The low resistance values given in the text were subtracted from the resistance of the pipette. Patch clamping of untreated mouse liver mitoplasts was carried out as in Sorgato et al (1989). Pipettes, pulled from Kimax-51 glass capillaries (Kimble Products), were coated with Silgard (Corning) and fire polished before use.…”

Section: Experimental Conditions Of Patch Clamping and Electrical Recmentioning

confidence: 99%

“…Mitochondrial fractions were suspended in 250 mM mannitol, 50 mM Hepes-KOH (pH 7.2) and 270 mM sucrose, 5 mM N-tris [hydroxymethyl] methyl-2-aminoethanesulfonic acid (pH 7), respectively. Untreated mouse liver mitoplasts (OM-free mitochondria) were prepared according to Sorgato et al (1989).…”

Section: Preparation Of Mouse Liver and Guinea Pig Non-synaptosomal Bmentioning

confidence: 99%

“…Liver mitochondria were prepared following the method described by Sorgato et al (1989) for cuprizone-untreated mouse liver mitochondria, while guinea pig brain mitochondria were obtained according to Nicholls (1978). Mitochondrial fractions were suspended in 250 mM mannitol, 50 mM Hepes-KOH (pH 7.2) and 270 mM sucrose, 5 mM N-tris [hydroxymethyl] methyl-2-aminoethanesulfonic acid (pH 7), respectively.…”

Section: Preparation Of Mouse Liver and Guinea Pig Non-synaptosomal Bmentioning

confidence: 99%

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Ionic permeability of the mitochondrial outer membrane

et al. 1992

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The ionic permeability of the outer mitochondrial membrane (OMM) was studied with the patch clamp technique. Electrical recording of intact mitochondria (hence of the outer membrane (OM], derived from mouse liver, showed the presence of currents corresponding to low conductances (less than 50 pS), as well as of four distinct conductances of 99 pS, 152 pS, 220 pS and 307 pS (in 150 mM KCl). The latter were voltage gated, being open preferentially at positive (pipette) potentials. Very similar currents were found by patch clamping liposomes containing the isolated OM derived from rat brain mitochondria. Here a conductance of approximately 530 pS, resembling in its electrical characteristics a conductance already attributed to mitochondrial contact sites (Moran et al. 1990), was also detected. Immunoblot assays of mitochondria and of the isolated OM with antibodies against the outer membrane voltage-dependent anion channel (VDAC) (Colombini 1979), showed the presence of the anion channel in each case. However, the typical electrical behaviour displayed by such a channel in planar bilayers could not be detected under our experimental conditions. From this study, the permeability of the OMM appears different from what has been reported hitherto, yet is more in line with that multifarious and dynamic structure which apparently should belong to it, at least within the framework of mitochondrial biogenesis (Pfanner and Neupert 1990).

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Section: Experimental Conditions Of Patch Clamping and Electrical Recmentioning

confidence: 99%

Section: Preparation Of Mouse Liver and Guinea Pig Non-synaptosomal Bmentioning

confidence: 99%

Section: Preparation Of Mouse Liver and Guinea Pig Non-synaptosomal Bmentioning

confidence: 99%

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Ionic permeability of the mitochondrial outer membrane

et al. 1992

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“…In the mean time several ion channels have been described: a 107 pS anion channel [1][2][3], now thought to be identical to the inner membrane anion channel (IMAC) which was first characterized by osmotic swelling of mitochondria [4,5], a 300 pS channel activated by targeting sequences of prepeptides [6], an ATP-sensitive K-channel [7; see also 8], and, finally, a large channel of still unknown molecular nature but high physiological importance, the permeability transition pore (PTP, also called MMC for mitochondrial mega channel) [9][10][11]. In the open state the PTP allows permeation of ions and uncharged molecules of up to 1.5 kDa.…”

Section: Introductionmentioning

confidence: 99%

Single-Channel Currents of the Permeability Transition Pore from the Inner Mitochondrial Membrane of Rat Liver and of a Human Hepatoma Cell Line

Loupatatzis

Seitz

Schönfeld³

et al. 2002

Cell Physiol Biochem

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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⁺ concentration 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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“…At the end of the 1980s, Sorgato et al [6], using the patch-clamp technique, described an inner mitochondrial membrane anion channel with a conductance of 108 pS. Subsequently, this 108-pS channel was located in patch-clamp experiments conducted on mitoplasts in the liver [7], heart [7], brain [8] and brown adipose tissue [9]. The properties of IMAC and the 108-pS channel seemed to be similar [10].…”

Section: Introductionmentioning

confidence: 99%

Stilbene derivatives inhibit the activity of the inner mitochondrial membrane chloride channels

Koszela-Piotrowska

Choma

Bednarczyk

et al. 2007

Cellular and Molecular Biology Letters

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Ion channels selective for chloride ions are present in all biological membranes, where they regulate the cell volume or membrane potential. Various chloride channels from mitochondrial membranes have been described in recent years. The aim of our study was to characterize the effect of stilbene derivatives on single-chloride channel activity in the inner mitochondrial membrane. The measurements were performed after the reconstitution into a planar lipid bilayer of the inner mitochondrial membranes from rat skeletal muscle (SMM), rat brain (BM) and heart (HM) mitochondria. After incorporation in a symmetric 450/450 mM KCl solution (cis/trans), the chloride channels were recorded with a mean conductance of 155 ± 5 pS (rat skeletal muscle) and 120 ± 16 pS (rat brain). The conductances of the chloride channels from the rat heart mitochondria in 250/50 mM KCl (cis/trans) gradient solutions were within the 70-130 pS range. The chloride channels were inhibited by these two stilbene derivatives: 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) and 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS). The skeletal muscle mitochondrial chloride channel was blocked after the addition of 1 mM DIDS or SITS, whereas the brain mitochondrial channel was blocked by 300 µM DIDS or SITS. The chloride channel from the rat heart mitochondria was inhibited by 50-100 μM DIDS. The inhibitory effect of DIDS was irreversible. Our results confirm the presence of chloride channels sensitive to stilbene derivatives in the inner mitochondrial membrane from rat skeletal muscle, brain and heart cells.

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Further investigation on the high-conductance ion channel of the inner membrane of mitochondria

Cited by 52 publications

References 41 publications

Ionic permeability of the mitochondrial outer membrane

Ionic permeability of the mitochondrial outer membrane

Single-Channel Currents of the Permeability Transition Pore from the Inner Mitochondrial Membrane of Rat Liver and of a Human Hepatoma Cell Line

Stilbene derivatives inhibit the activity of the inner mitochondrial membrane chloride channels

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