RESUMO
The neuroprotective effect of diazepam has been demonstrated in global ischemia models in vivo and in vitro [Neuroscience (2000) 471]. We studied the effect of diazepam on lesion volume in a photothrombotic model of focal brain ischemia in the rat, and the relation of such effect to time of drug administration. For this purpose we induced photochemically a focal brain lesion, and added diazepam 10 mg/kg intraperitoneally just before, at 1 and 4 h after lesion induction. After 24 h the rats were decapitated, and lesion volumes of 27 diazepam-treated rats were compared with that of 12 controls. Treated animals had a significant smaller lesion volume than controls, except those who received diazepam before induction of the lesion. We conclude that diazepam is neuroprotective in focal brain ischemia even when administered up to 4 h after ischemia onset.