Müller cell function during spreading depression in frog retina.
K+ potentials were investigated using K+ microelectrodes in frog (Rana pipiens) retinas conditioned for spreading depression (SD) by Cl--free Ringer's solution. A marked increase in outside K+ concentration, [K+]O, maximal in the inner plexiform layer, was observed during SD. This [K+]o change resembled the simultaneously recorded membrane potential change in Müller cells, suggesting that these cells act as K+ electrodes. Intracellular recording with K+ electrodes in Müller cells showed that upon SD the [K+]i (inside) of Müller cells increases and therefore immediately starts to cleanse the extracellular space of the excess of K+ which, evidence suggests, is mainly caused by pathologically enhanced synaptic activity in the inner plexiform layer.
D000818:Animals; D066298:In Vitro Techniques; D008564:Membrane Potentials; D008954:Models, Biological; D009457:Neuroglia / Q000502:physiology*; D011188:Potassium / Q000378:metabolism*; D011894:Rana pipiens; D012160:Retina / Q000502:physiology*
D011188:Potassium