Ascorbic acid during cerebral ischemia in newborn piglets.

We measured ascorbic acid (reduced and oxidized) in brain, CSF and blood, before, during and after cerebral ischemia in newborn piglets. Bilateral carotid ligation induced a 54% decrease in cerebral blood flow (p < 0.01) and a 43% decrease in the cerebral metabolic rate of oxygen (p < 0.01). After ischemia and reperfusion, we obtained a 60% decrease (p < 0.01) in total brain ascorbic acid content. CSF ascorbic acid increased during reperfusion: +60% at 30 min (p < 0.001) and +160% at 120 min (p < 0.05). Blood ascorbic acid content did not change. These changes and the absence of massive oxidation of ascorbic acid in brain tissue suggest release of ascorbic acid by the brain during ischemia.