Inflammatory stimuli induce a new K+ outward current in cultured rat microglia.
Membrane currents of cultured rat microglia were recorded with the whole-cell patch clamp technique. Undifferentiated microglia express only inwardly rectifying K+ channels. However, treatment of the cells with bacterial lipopolysaccharide, interferon-gamma, or their incubation in hydrophobic teflon bags, procedures that promote microglial differentiation, induced the expression of an additional outward current. Cycloheximide prevented the development of this conductance indicating the synthesis of a new channel protein. The reversal potential of the outward current was near to the K+ equilibrium potential; the current was abolished by intracellular Cs+ or extracellular 4-aminopyridine, and was depressed by extracellular tetraethylammonium. Hence, the channels involved appear to be highly selective for K+; their possible function is a rapid termination of depolarizing shifts of the membrane potential.
Nörenberg
W
W
Department of Pharmacology, University of Freiburg, FRG.
Gebicke-Haerter
P J
PJ
Illes
P
P
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism*; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
D008070:Lipopolysaccharides; D015221:Potassium Channels; D007371:Interferon-gamma; D003513:Cycloheximide; D015761:4-Aminopyridine