[Delayed treatment with dextromethorphan can reduce ischemic retinal damage in rabbit].

Previous studies have suggested that prophylactic treatment by dextromethorphan (DEX), N-methyl-D-aspartate (NMDA) receptor antagonist can protect the retina against ischemia. To investigate the effect of DEX on the proceeding ischemic retina, 0.1% DEX hydrobromide was intravenously administered in rabbits immediately (group A), 1 hour (group B) or 2 hours (group C) after the release from ischemia induced by increasing intraocular pressure to 130 mmHg for 90 min. Normal saline was infused immediately after the release from ischemia as control rabbits. Retinal function was monitored by recording electroretinogram (ERG). Twenty four hours after the release of ischemia, the recovery rates of ERG.b-wave amplitudes in groups A, B and C were 61.3 +/- 3.3, 52.2 +/- 9.0 and 43.6 +/- 8.4% of the preischemic amplitude, respectively. The recovery rate of the group A was higher than that of the control (41.9 +/- 10.6%), while no significant differences were seen between groups B or C and the control. The results suggest that DEX can protect the retina if it is administered immediately after the release of ischemia.