Levels of low molecular weight scavengers in the rat brain during focal ischemia.

Ascorbic acid, cysteine, glutathione, uric acid, tyrosine and tryptophan were quantified in samples of frontoparietal cortex, striatum, hippocampus and cerebellum from both sides of rat brain 0.5 h, 4 h and 24 h after focal ischemia. Cysteine, tyrosine and tryptophan were increased in cortex and striatum at 0.5 h, returning afterwards to normal. Uric acid was increased, whereas ascorbic acid and glutathione were correspondingly decreased. Although changes can be explained primarily by energy failure they are also consistent with free radical activity during early stages of ischemia.