Control of extracellular potassium levels by retinal glial cell K+ siphoning

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Science  14 Sep 1984:
Vol. 225, Issue 4667, pp. 1174-1175
DOI: 10.1126/science.6474173


Efflux of K+ from dissociated salamander Muller cells was measured with ion-selective microelectrodes. When the distal end of an isolated cell was exposed to high concentrations of extracellular K+, efflux occurred primarily from the endfoot, a cell process previously shown to contain most of the K+ conductance of the cell membrane. Computer simulations of K+ dynamics in the retina indicate that shunting ions through the Muller cell endfoot process is more effective in clearing local increases in extracellular K+ from the retina than is diffusion through extracellular space.

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