İçeri Doğrultucu Potasyum Kanalları ve Epilepsi

İçeri doğrultucu potasyum kanalları “inwardly rectifying potassium channels” (Kir kanalları), aksiyon potansiyelinde hücre içine K+ iyonu taşıyarak, aksiyon potansiyelini membran dinlenim potansiyeline stabilize etmekle görevlidir. Yakın dönemde yapılan fonksiyonel çalışmalarda, başta epilepsi olmak üzere çeşitli nörolojik hastalıklarda ilişkisi olduğu belirlenen Kir kanallarının alt ailelerinden olan Kir4.1 kanalının fonksiyon bozukluğuna bağlı olarak hücre içine K+ iyonu taşıyamadığı görülmüştür. Bu veriyi destekleyen araştırmalarda ise, ekstraselüler ortamda glutamat ile K+ iyonu dengesinin bozulması sonucu hücrenin hiperaktiviteye gidebileceği düşünülmüştür. 7 alt aileye sahip Kir kanallarının epilepsi mekanizmasındaki rolü üzerine yapılan araştırmalarda şimdiye kadar Kir2.x, Kir3.x, Kir4.1 ve Kir6.2 kanallarının fonksiyonel olarak değişebileceği gösterilmiştir. Klinik ve deneysel araştırmalardan elde edilen kanıtların epilepsinin kardiyak fonksiyonu etkileyebileceğini göstermektedir, fakat bunun moleküler mekanizması henüz tam olarak bilinmemektedir. Bu nedenle, ayrıca kardiyak Kir kanalları da ele alınmıştır.

Anahtar Kelimeler:

Kir kanalları, K+ iyonu, hiperaktivite, disfonksiyon, epilepsi

Inwardly Rectifying Potassium Channels and Epilepsy

Inwardly rectifying potassium channels (Kir channels) are responsible for restraining the action potential of the membrane by stabilizing the membrane potential for relaxation by transporting K+ ions into the cell. Recent functional studies have shown that the Kir4.1 channel, a subset of the Kir channels, which is associated with various neurological disorders, primarily epilepsy, cannot carry K+ ions into the cell due to dysfunction. In studies supporting this data, it was thought that the glutamate and K+ ion unbalance in the extracellular medium could result in hyperactivity of the cell. Investigations into the role of Kir channels with 7 subfamilies in the mechanism of epilepsy have shown that the Kir2.x, Kir3.x, Kir4.1 and Kir6.2 channels functionally may change. Evidence obtained from clinical and experimental studies show that epilepsy could affect cardiac function; however, the molecular mechanism underlying has not been fully understood yet. For this reason, cardiac Kir channels are also considered.

Keywords:

Kir channels, K+ ion, hyperactivity, dysfunction, epilepsy,

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