[Extracellular potassium in the frog retina and its light-induced changes].
Similar downhill gradients of [K]0 were revealed in the aspartate--treated dark--adapted frog retina and in the eye cup without aspartate. [K]0 in the receptor layer is 8 X 10(-3) M, while in the proximal retina it is nearly 2.7 X 10(-3) M. Illumination decreased [K]0 in the receptor layer to 2.5 X 10(-3) M. The dark level and the light-induced changes of [K]0 were practically unaltered when Ba2+ ions suppressed the slow PIII and the resting transretinal glia potential blocking up the Müller cells permeability for K+. The findings suggest that [K]0 around the receptor space is regulated by red rods with no interference from the Müller cells or pigment epithelial cells. The amplitude of [K]0 changes seems to be physiologically significant.
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D001464:Barium / Q000494:pharmacology; D003623:Dark Adaptation / Q000187:drug effects / Q000528:radiation effects; D066298:In Vitro Techniques; D008027:Light; D008564:Membrane Potentials / Q000187:drug effects / Q000528:radiation effects; D009457:Neuroglia / Q000187:drug effects / Q000528:radiation effects; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000187:drug effects / Q000528:radiation effects; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000528:radiation effects; D011188:Potassium / Q000502:physiology / Q000528:radiation effects*; D011896:Rana temporaria; D012160:Retina / Q000187:drug effects / Q000528:radiation effects*
D001464:Barium; D001224:Aspartic Acid; D011188:Potassium
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