Low brain glutathione and ascorbic acid associated with dopamine uptake inhibition during rat's development induce long-term cognitive deficit: relevance to schizophrenia

Schizophrenia is associated with a cerebral glutathione deficit, which may leave the brain susceptible to oxidants. To study the consequences of a glutathione deficit, we treated developing rats with L-buthionine-(S,R)-sulfoximine (BSO), an inhibitor of glutathione synthesis, and later investigated their behaviour until adulthood. Since rodents may in some occasions compensate for a glutathione deficit by ascorbic acid (AA), we used Osteogenic Disorder Shionogi (ODS) mutant rats, which like humans, cannot synthetize ascorbic acid. Moreover, as hyperactivity of the dopaminergic system may be associated with schizophrenia, some rats were treated with the dopamine uptake inhibitor GBR 12909. Whereas ODS rats treated with either BSO or GBR 12909 alone had normal behaviour, rats treated with both BSO and GBR 12909 failed to discriminate between familiar and novel objects although other behaviours proved to be normal. In contrast, nonmutant rats were not affected by treatment with BSO and GBR 12909. Our results suggest that low brain glutathione and ascorbic acid levels associated with a perturbation of the dopaminergic system actively participate in the development of some cognitive deficits affecting schizophrenic patients.