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Interrelationships between ornithine, glutamate and GABA—I. Feed-back inhibition of ornithine aminotransferase by elevated brain GABA levels

1987; Elsevier BV; Volume: 10; Issue: 3 Linguagem: Inglês

10.1016/0197-0186(87)90115-x

1872-9754

Nikolaus Seiler, Helen Spraggs, Geneviève Daune,

Neuroscience and Neuropharmacology Research

In this work new methods for the determination of ornithine (Orn) and l-ornithine:2-oxoacid aminotransferase (OAT) activity are described. These methods were used to demonstrate linear interrelationships between brain GABA and Orn concentrations. Brain GABA levels were modulated by administration of vigabatrin (4-aminohex-5-enoic acid), a specific inactivator of GABA-T, which is not an inhibitor of OAT. The results suggest feed-back inhibition of OAT by GABA, a mechanism which is compatible with the assumption that Orn may serve in certain neurons as a precursor of glutamate and GABA.