Recovery of ERG b-wave responses after a photobleach in drug- and vehicle-treated ground squirrels. After baseline ERG recordings, the animals were subjected to a 10-min photobleach that completely suppressed b-wave responses. They were subsequently monitored for ERG recovery with flashes giving approximately half-maximal responses (100 cd·s/m2, except for the animal whose responses are shown in the lower graph of the 80 mg/kg/day MB-001 column, which required 300 cd·s/m2 to elicit midsaturating responses). Data shown as blue circles were obtained at day 1 before drug or vehicle treatment. Data shown as red circles were obtained after three consecutive days of vehicle or drug treatment at the indicated dose. The later ERGs were measured ∼2 h after the final dose of drug. Each panel shows data from a single animal. MB-001 at either dose greatly delays the recovery of cone sensitivity. Fenretinide also delayed, to a smaller degree, cone sensitivity recovery in two of the three treated animals.
