Wyniki wyszukiwania - Biblioteka Nauki

1

Ogólnopolska konferencja użytkowników oprogramowania statystycznego R

100%

Beresewicz M.

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nr 01

2

Role of mitochondria in the delayed neuronal death after transient brain ischemia n vivo

51%

Kowalczyk J. E. , Beresewicz M. , Zablocka B.

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tom 53

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nr Supplement 1

3

PKC delta and beta translocation to mitochondria correlates with opposite susceptibility of hippocampal regions to ischemic insult

51%

Kowalczyk E. , Beresewicz M. , Zablocka B.

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2006

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tom 66

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nr 4

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Estymacja liczby cudzoziemców w Polsce z wykorzystaniem metody capture-recapture

51%

Beresewicz M. , Gudaszewski G. , Szymkowiak M.

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2019

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tom 64

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nr 10

5

Diazepam and cyclosporin A:the promising neuroprotectants

51%

Sarnowska A. , Beresewicz M. , Zablocka B. , Domanska-Janik K.

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2006

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tom 66

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nr 4

6

A novel voltage-gated potassium channel in hippocampal mitochondria

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Kowalczyk J. E. , Bednarczyk P. , Beresewicz M. , Dolowy K. , Szewczyk A. , Zablocka B.

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nr 1

EN

Transient cerebral ischemia is known to induce endogenous adaptive mechanisms such as the activation of mitochondrial ATP-sensitive potassium channels or calcium-sensitive largeconductance potassium channels that can prevent or delay neuronal injury. In this study a single channel activity was measured after patch-clamp of the mitoplasts isolated from control gerbil hippocampus. In 70% of the all patches, a potassium selective current was recorded with mean conductance 109 ± 6 pS in symmetrical 150 mM KCl solution. Patch-clamp single channel studies protein showed properties of the voltage-gated potassium channel (Kv channel): it was blocked by negative voltage and margatoxin (MgTx) a specifi c Kv1.3 inhibitor. The inhibition by MgTx was no reversed. The channel was not affected by the other Kv1.3 channel blocker agitoxin-2 at nanomolar range. Additionally, we showed that ATP/Mg2+ complex and low or high concentration of Ca2+ ions have no effects on observed activity of ion channel. Mitochondrial localization of Kv1.3 was verifi ed by western blots using antibodies recognizing peptides located in N- or C-terminal of plasma membrane Kv1.3 protein. N-terminal specifi c antibodies recognized proteins with molecular masses around 95, 62 and 40 kDa in plasma membrane and 60 kDa in mitochondria while C-terminal specifi c antibodies recognized 40 kDa protein in mitochondria. Mitochondrial localization of Kv1.3 protein was also shown by immunohistochemistry. We conclude that gerbil hippocampus mitochondria contain voltagegated potassium channel (mitoKv) with properties similar to the surface membrane Kv1.3 channel which can play an important regulatory role for protection with respect of ischemia-reperfusion phenomena. Supported by Polish Mitochondrial Network MitoNet.pl

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Voltage-gated potassium channel in hippocampus mitochondria

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Bednarczyk P. , Kowalczyk J. E. , Beresewicz M. , Dolowy K. , Szewczyk A. , Zablocka B.

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nr 1

EN

Transient cerebral ischemia is known to induce endogenous adaptive mechanisms such as the activation of mitochondrial ATP regulated or Ca2+ regulated large conductance potassium channels that can prevent or delay neuronal injury. However, molecular mechanism of this effect remains unclear. In this study, a single channel activity was measured with patch-clamp of the mitoplasts isolated from gerbil hippocampus. In 70% of the all patches, a potassium selective current with properties of the voltage-gated potassium channel (Kv type channel) was recorded with mean conductance 109 ± 6 pS in symmetrical 150 mM KCl solution. Detected channel was blocked by negative voltage and margatoxin (MgTx) a specific Kv1.3 channel inhibitor. The inhibition by MgTx was irreversible. We observed that ATP/Mg2+ complex or Ca2+ ions had no effects on observed activity of ion channel. Additionally, we showed that agitoxin-2 (AgTx-2), potent inhibitor of the voltage-gated potassium channels, was without effect on channel activity. This observation suggests that mitochondrial voltage-gated potassium channel can represent different molecular structure without affinity to AgTx-2 in compare to surface membrane channels. Also, Western blot analysis of mitochondria isolated from gerbil hippocampus and immunohistochemistry on gerbil brain sections confirm the expression of Kv1.3 protein in mitochondria. All together, we conclude that gerbil hippocampal mitochondria contain voltage-gated potassium channel (mitoKv1.3 channel) with properties similar to the surface membrane Kv1.3 channel which can influence function of mitochondria in physiological and pathological conditions. This study was supported by the grant from the Ministry of Science and Higher Education (P-N/31/2006) and Polish Mitochondrial Network MitoNet.pl. P.B. would like to acknowledge to prof. Detlef Siemen for teaching patch-clamp and more discussion during postdoc in Magdeburg supported by EMBO (2006) and DAAD (2008).