Acid-base balance affects electroretinogram b- and c-wave differentially in the perfused cat eye

The pH concentration strongly affects b- and c-waves of the vitreal direct coupled electroretinogram (DC/ERG) in the arterially perfused cat eye, in which acid-base balance can be changed temporarily excluding extraocular regulation (Niemeyer and Steinberg, 1984; Dawis et al., 1984, 1985; Niemeyer et al., 1984;. To increase pHi we injected NaOH and NH4Cl or substituted for control perfusate low PCO2, low HCO3- perfusate. This induced an increase in b-wave and a decrease in c-wave amplitude. To decrease pHi we injected HCl and NaHCO3-, increased PCO2, or substituted high PCO2, high HCO3- perfusate. This induced a decrease in b-wave and an increase in c-wave amplitude. Covariation between standing potential and c-wave was found in only three of the seven experimental conditions. The change in standing potential was faster than that in the ERG waves. It is suggested that changes in pH affect primarily the retinal component of the c-wave. The b-wave consistently followed the direction of the expected change in pHi. All effects were reversible.