Modulation and mechanisms of electroretinogram recovery after short-term retinal ischemic injury

This study examines whether electroretinogram recovery after short-term (15- or 20-min) ischemia is enhanced by agents (catalase and dextromethorphan) that are known to enhance recovery after longer (60-75 min) periods of ischemia. Under both light-adapted and dark-adapted conditions, Dutch rabbits were exposed to two sequential sets of short-term ischemia, each followed by 60 min of reperfusion during which the electroretinogram was monitored. Catalase or dextromethorphan was administered intravenously before the second reperfusion period. Control experiments showed that electroretinogram recovery curves from sequential ischemic episodes were similar, and neither intravenous catalase nor dextromethorphan increased the rate or magnitude of electroretinogram recovery. This negative result suggests that the mechanisms of injury or recovery after short-term retinal ischemia may be different from those operating after 60-75 min of ischemia.