Role of nitric oxide on GABA, glutamic acid, activities of GABA-T and GAD in rat brain cerebral cortex

The results of the present study clearly shows that a correlation exists be tween nitric oxide (NO) and gamma-aminobutyric acid transaminase (GABAT-T) activity as well as gamma-aminobutyric acid (GABA), glutamic acid and the a ctivity of glutamic acid decarboxylase (GAD). Supporting of this 10 min aft er the administration of L-Arginine (L-Arg) increased GABA concentration an d diminished the activity of GABA-T. There was no change in GAD activity an d glutamic acid level. Administration of convulsion inducing agent Picrotox in (PCT) decreased the NO concentration in the brain and enhanced the activ ity of GABA-T, and the fact that the NOS inhibitor (N-G-nitro-L-Arg methyl ester (L-NAME) diminished the activity of NOS and increased the activity of GABA-T provide another support for the involvement of NO on GABA-T activit y. The present study clearly showed that high concentrations of NO in the b rain suppresses the activity of GABA-T. (C) 1999 Published by Elsevier Scie nce B.V. All rights reserved.