Abstract
Effects of AOAA on free amino acids in rat brain and glutamate-oxaloacetate transaminase (GOT) activities in rabbit muscle were investigated. The following results were obtained.
1) γ-aminobutyric acid (GABA) level in rat brain was increased following the intraperitoneal administration of 20-60 mg/kg of AOAA. Namely, it showed about 3 times as much as control level 1 hour after the administration. Then gradually it decreased with the time elapsed. However, even 48 hours after the administration it showed about 1.5 times as much as the control level.
Except GABA, free amino acids in rat brain, such as glutamic acid, aspartic acid, glutamine were induced marked reductions in contrast with the elevation of GABA level.
2) AOAA and hydroxylamine inhibited GOT activity in rabbit skeletal muscle. AOAA showed more potent inhibition than hydroxylamine to the GOT activity. PI50 at the final concentration of AOAA and hydroxylamine were 1.6×10-5 M and 8.0×10-4 M respectively.
Against L-aspartate, one of the substrates of GOT, both of the compounds showed competitive inhibition to GOT activity, but against α-ketoglutarate, another substrate of GOT, both of them showed mixed type inhibition.
