LONG-TERM ISOLATION OF WISTAR RATS ALTERS BRAIN MONOAMINE TURNOVER, BLOOD CORTICOSTERONE, AND ACTH

In this work, we in-investigated neurochemical parameters in the brain of male Wistar rats after isolation times (13 weeks) longer than thos e previously reported with this strain: a large majority of animals be came muricidal under these conditions. Changes in monoamines turnover in hippocampus, cortex, and cerebellum and, in the blood, ACTH, and co rticosterone were investigated. Monoamine turnover was analysed using two different approaches: first, by measuring neurotransmitter and met abolite levels and second, by measuring rate of accumulation of the pr ecursor after decarboxylase. Both methods revealed a significant incre ase in catecholamine turnover in the three regions studied after the 1 3-week isolation; in contrast, only a modest elevation of 5-hydroxytry ptophan accumulation was obtained in cortex and cerebellum of isolated rats. We also observed a decrease in corticosterone levels in blood c oncomitant with an increase of ACTH.