BACKGROUND: Both excitatory and inhibitory amino acids modulate central neuronal activity following peripheral nerve tissue injury.OBJECTIVE: To establish whether mononeuropathy induced by chronic constriction injury or by sectioning of the sciatic nerve affects neurotransmitter amino acid levels in the rat brain areas.METHODS: Glutamine, glutamic acid, gamma-aminobutyric acid (GABA) and aspartic acid in the hindbrain, midbrain and hypothalamus of rats were measured by high performance liquid chromatography 14 days after surgery.RESULTS: After monolateral nerve ligation an increase in glutamine and a decrease in GABA levels in all brain areas were observed, with no side preference. The section of the sciatic nerve did not cause any modification in amino acid levels.CONCLUSIONS: The results allow one to differentiate more clearly classic models of mononeuropathy from a biochemical point of view. Moreover, results indicate that continuous neuronal stimulation induced by nerve constriction is able to modify some amino acid pathways at a supraspinal level.