Modulation of Kir4.1 and Kir4.1-Kir5.1 channels by extracellular cations
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
This work demonstrates that extracellular Na(+) modulates the cloned inwardly rectifying K(+) channels Kir4.1 and Kir4.1-Kir5.1. Whole-cell patch clamp studies on astrocytes have previously indicated that inward potassium currents are regulated by external Na(+). We expressed Kir4.1 and Kir4.1-Kir5.1 in Xenopus oocytes to disclose if Kir4.1 and/or Kir4.1-Kir5.1 at the molecular level are responsible for the observed effect of [Na(+)](o) and to investigate the regulatory mechanism of external cations further. Our results showed that Na(+) has a biphasic modulatory effect on both Kir4.1 and Kir4.1-Kir5.1 currents. Depending on the Na(+)-concentration and applied voltage, the inward Kir4.1/Kir4.1-Kir5.1 currents are either enhanced or reduced by extracellular Na(+). The Na(+) activation was voltage-independent, whereas the Na(+)-induced reduction of the Kir4.1 and Kir4.1-Kir5.1 currents was both concentration-, time- and voltage-dependent. Our data indicate that the biphasic effect of extracellular Na(+)on the Kir4.1 and Kir4.1-Kir5.1 channels is caused by two separate mechanisms.
Originalsprog | Engelsk |
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Tidsskrift | Biochimica et Biophysica Acta - Biomembranes |
Vol/bind | 1788 |
Udgave nummer | 9 |
Sider (fra-til) | 1706-1713 |
Antal sider | 8 |
ISSN | 0005-2736 |
DOI | |
Status | Udgivet - 2009 |
ID: 14640424