BEHAVIORAL-EFFECTS OF VIGABATRIN CORRELATED WITH WHOLE-BRAIN GAMMA-AMINOBUTYRIC-ACID METABOLISM IN AUDIOGENIC SENSITIVE RATS

The present study evaluates dose-dependent behavioral effects of acute ly or subacutely administered single doses of vigabatrin (gamma-vinyl gamma-aminobutyric acid, gamma-vinyl GABA, CAS 60643-869) in audiogeni c sensitive rats, in correlation with whole brain GABA metabolism. The re was a discrepancy in timing between behaviorally observed maximal a ntiepileptic protection (4 h after i.p. administration of gamma-vinyl GABA) and on the other hand maximal inhibition of GABA-transaminase ac tivity and maximal increase of whole brain GABA content (24 h after i. p, administration of gamma-vinyl GABA). This suggests that the antiepi leptic properties of gamma-vinyl GABA not only depend on GABA-ergic ne urotransmission. A possible explanation is a gamma-vinyl GABA-induced decrease of excitatory amino acids or increased glycine concentrations in the brain.