MODULATION AND MECHANISMS OF ELECTRORETINOGRAM RECOVERY AFTER SHORT-TERM RETINAL ISCHEMIC-INJURY

This study examines whether electroretinogram recovery after short-ter m (15- or 20-min) ischemia is enhanced by agents (catalase and dextrom ethorphan) that are known to enhance recovery after longer (60-75-min) periods of ischemia. Under both light-adapted and dark-adapted condit ions, Dutch rabbits were exposed to two sequential sets of short-term ischemia, each followed by 60 min of reperfusion during which the elec troretinogram was monitored. Catalase or dextromethorphan was administ ered intravenously before the second reperfusion period. Control exper iments showed that electroretinogram recovery curves from sequential i schemic episodes were similar, and neither intravenous catalase nor de xtromethorphan increased the rate or magnitude of electroretinogram re covery. This negative result suggests that the mechanisms of injury or recovery after short-term retinal ischemia may be different from thos e operating after 60-75 min of ischemia.