EFFECTS OF SOME COMMON CATIONS ON ELECTRORETINOGRAM OF THE TOAD

Abstract

Effects of some common cations on electroretinogram (ERG) were studied using the isolated retina of the Japanese toad.1. The isolated retina could be maintained in good condition for several hours, if preserved half immersed in Ringer's. Ringer's was a favorable substituting fluid for the retina.2. The presence of Na+ was indispensable for both a-and b-wave of ERG. But b-wave was far more susceptible to the lack of Na+ in the medium. When the retina was immersed in an isotonic glucose solution, b-wave disappeared and only the negative component remained.3. The amplitude of this isolated negative component was found to increase if Na+ was added to the bathing fluid. This was shown very clearly if reappearance of b-wave was avoided by adding a suitable amount of aspartic acid to the bathing fluid. Aspartic acid was found to have a very strong and specific depressant action on b-wave of ERG.4. K+ had a depressing effect on b-wave of ERG, but it seemed to have no augmentative effect on negative component.5. Methods of eliminating b-wave from ERG and some properties of the thus isolated negative component were discussed.