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Kajma MiP2010

From Bioblast
Kajma A, Bednarczyk P, Szewczyk A (2010) Mitochondrial potassium ion channels regulated by polyunsaturated fatty acid.

Link: Abstracts Session 1

Kajma A, Bednarczyk P, Szewczyk A (2010)

Event: MiP2010

Arachidonic acid (AA) is a polyunsaturated fatty acid (PUFA) which is highly concentrated in the membranes of the neuronal cells. Pathological conditions in the brain, such as ischemia increase the levels of AA in the cytoplasm [1]. Several lines of evidence indicate that the potent neuroprotective effect of PUFA may be linked with potassium channels. Moreover recent evidence suggests that potassium transport via channels presented in the inner mitochondrial membrane can trigger neuroprotection [2].

In our study a single channel activity was measured with the use of patch-clamp of the mitoplasts isolated from embryonic hippocampal neurons. Mitoplasts were prepared from the sample of the mitochondria by addition to a hypotonic solution to induce swelling following outer membrane rapture.

Our data provide evidence for the presence of large-conductance calcium activated potassium channels (mtBKCa) in the inner mitochondrial membrane of rat hippocampus. The channel conductance calculated based on current-voltage relations was equal to 288 pS. The activity of the channel deceased at low calcium concentration. Additionally, the channel activity was blocked by paxilline (inhibitor of the BKCa types channels). Moreover we demonstrated that the probability of opening of this channel is increased after the application of arachidonic acid. We also identified a novel channel which has current-voltage characteristics similar to the rectifying potassium channels. The channel conductance was equal to 60 pS. Patch-clamp studies showed that this channel is not sensitive to the known activators and inhibitors of mitochondrial potassium channels, but is regulated by arachidonic acid.

In summary, the findings presented in this study provide new functional data suggesting the presence of the two channels in the rat hippocampus mitochondria: BKCaโ€“type and rectifying potassium channel, both regulated by arachidonic acid.

Grant sponsor: Ministry of Science and Higher Education P-N/031/2006

1. Adibhatla RM, Hatcher J F (2006) Phospholipase A2, reactive oxygen species, and lipid peroxidation in cerebral ischemia. Free Radical Biol. Med. 40: 376-387.

2. Szewczyk A, Jarmuszkiewicz W, Kunz WS (2009) Mitochondrial potassium channels. IUBMB Life 61: 134-143.


โ€ข O2k-Network Lab: PL_Warsaw_Szewczyk A, PL Warsaw Bednarczyk P


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