Electrophysiological correlates of rod outer segment disc shedding in rabbit retina.

We hypothesize that the b-wave of the electroreginogram (ERG) can provide a precise, noninvasive measure of the morning rod disc shedding event. ERGs were recorded in the dark from photoentrained rabbits using a 500 nm test light. Histological examination of the pigment epithelium confirmed that an increase in large phagosome content occurred shortly after light onset. In albino rabbits the b-wave decreased in amplitude at about 30 min after the time of normal light onset. The corresponding decrease in sensitivity required to produce this change in amplitude was 0.11 log unit. No ERG effect was seen in pigmented rabbits.