Effects of maintained illumination upon [K+]0 in the subretinal space of the isolated retina of the toad.
Illumination of the vertebrate retina evokes a transient decrease in extracellular potassium concentration, [K+]0, in the subretinal space. During maintained illumination, [K+]0 recovers toward its dark-adapted level. The mechanisms most likely to contribute to this recovery process were examined by using K+-selective microelectrodes to measure [K+]0 in the isolated retina of the toad. Bufo marinus. Although both diffusion of K+ and changes in the rod membrane voltage contribute to the recovery of [K+]0 during maintained illumination, other factors are likely to be involved as well. It is suggested that this recovery process could be due in part to inhibition of the Na+/K+ pump in the rod photo-receptors during maintained illumination.
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D001464:Barium / Q000494:pharmacology; D001693:Biological Transport, Active / Q000187:drug effects; D002024:Bufo marinus; D003623:Dark Adaptation; D004058:Diffusion; D004307:Dose-Response Relationship, Radiation; D005074:Evoked Potentials, Visual / Q000187:drug effects; D066298:In Vitro Techniques; D008027:Light; D008564:Membrane Potentials / Q000187:drug effects; D011188:Potassium / Q000378:metabolism*; D012160:Retina / Q000378:metabolism*; D013997:Time Factors
D001464:Barium; D001224:Aspartic Acid; D011188:Potassium