Acute effects of an aminosteroid on microdialytically measured parameters after experimental middle cerebral artery occlusion in the rat

The effects of the neuroprotective aminosteroid U74389G were monitored micr odialytically in rat cortex during 4 h after permanent middle cerebral arte ry occlusion. Either U74389G or vehicle only was administered one hour befo re and 2 h sifter operation. The dialysate was analysed for on-line pH, asc orbic acid, uric acid, glucose and lactate. In aminosteroid treated animals the levels of ascorbic and uric acids were lower in dialysates after occlu sion, total release of lactate was significantly reduced and online pH was significantly higher than in control animals. Lesion volume at 4 h, which w as significantly reduced in treated animals, correlated positively with asc orbic acid release and on-line pH. Results suggest that neuroprotective eff ects of aminosteroids might be explained by: (a) preservation of intracellu lar levels of the radical scavenger ascorbic acid with possible concomitant reduction of glutamate release; and (b) reduced lactate release and increa sed pH which might influence oedema positively.