Inward and outward rectifying potassium currents set membrane potentials in activated rat microglia

초록

Activation of cultured rat microglial cells with lipopolysaccharide (LPS), induced outward rectifying K+ (Kv) current in addition to already existing inward rectifying K+ current (K-IR) BY measuring zero-current membrane-potentials using whole-cell patch-clamp method, we showed that K-V current plays a direct role in setting membrane potential to near -45 mV. Since the membrane potentials of microglia show two prominent peaks at -45 and -70 mV, we hypothesize that K-IR current might set the membrane potential to near -70 mV. We observed that cells with larger K-IR current had a zero-current membrane-potential at around -70 mV, and that blocking of K-IR current with Ba2+ depolarized membrane potentials to near -45 mV. These results indicate that the amounts of K-IR, and K-V current determine the zero-current membrane-potentials in LPS-activated microglia. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

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