Dextromethorphan reduces neocortical ischemic neuronal damage in vivo.

The dextrorotatory morphinan dextromethorphan (DM), a clinically tested antagonist of the N-methyl-D-aspartate (NMDA) receptor-channel complex, was tested in an in vivo model of acute transient focal cerebral ischemia. Rabbits were randomly assigned to pretreatment with a 20 mg/kg i.v. bolus followed by 10 mg/kg/h of 0.4% DM in normal saline (NS), or with an equivalent volume of NS alone. They then underwent 1 h occlusion of the left internal carotid artery an anterior cerebral artery followed by 4 h of reperfusion. DM-treated animals showed a significant decrease in the percentage of severe neocortical ischemic neuronal damage (10.5%), as compared to NS-treated animals (49.6%).