Effect of blockade of synthesis of nitric oxide by L-NAME on the level of free amino acids and biogenic amines in the brain cortex of rats with subtotal cerebral ischemia

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Mechanisms of development of ischemic stroke are complex and have not been fully established. The aim of this study was to estimate the changes in the pool of free amino acids and biogenic animes in the brain cortex of rats with subtotal cerebral ischemia (SCI) and treated with L-NAME. Experiment was made on 18 rats: 12 animals were undergoing bilateral filament occlusion of arteries carotid, 6 of them were treated with L-NAME. The analyses of free amino acids levels in the blood plasma extracts were carried out by reversed phase HPLC.Concentrations of several amino acids were elevated during SCI including aspartate, b-alanine, valine and leucine. In contrast, the levels of glutamate, asparagine, treonine, gamma-aminobutiric acid, tyrosine and 5-hydroxiindolylacetate were decreased. The administration of L-NAME partially prevented the imbalance of the amino acids pool due to SCI by normalizing the levels of aspartate, glutamate, asparagine, methionine, gamma-aminobutiric acid, b-alanine, 5-hydroxiindolylacetate. However, the administration of L-NAME has induced an additional imbalance in the amino acids pool in the brain cortex (decrease in the levels of glutamine, histidine, taurine, tryptophan, phenylalanine, tyrosine (in comparison to SCI) and decrease in the levels of treonine and arginine. The imbalance of the amino acids pool induced by the administration of L-NAME during SCI is more severe than the imbalance caused by SCI.