Use of an alternating current amplifier when recording the ERG c-wave to evaluate the function of retinal pigment epithelial cells in rats.

Abstract

We studied the conditions under which c-waves of the electroretinogram (ERG), that represent retinal pigment epithelium (RPE) function, were detectable using an alternating current (AC) amplifier and whether the c-wave recorded using an AC amplifier was useful for evaluating RPE function. We recorded ERG responses in rats to 5s stimuli under the conditions in which the low-cut frequency and the stimulus luminance were varied. In addition, changes in ERGs were studied after intravenous injection of sodium iodate (SI) to induce RPE degeneration. The c-wave was detected clearly when the frequency of the low-cut filter was set at 0.01Hz and light stimulus luminances were ≥ - 1.0 log cd/m2. The c-wave was attenuated earlier than other waves (e.g., a-wave and b-wave) after SI administration. The c-wave was easily detectable using an AC amplifier with the low-cut filter set at 0.01Hz. Using the AC amplifier may allow easier c-wave recording, compared with the conventional use of a direct current (DC) amplifier, and could be useful for evaluating RPE function.