Acute administration of l-tyrosine alters energetic metabolism of hippocampus and striatum of infant rats

• Published in: International journal of developmental neuroscience 2013-08, Vol.31 (5), p.303-307
• Main Authors: Ramos, Ândrea C., Ferreira, Gabriela K., Carvalho-Silva, Milena, Furlanetto, Camila B., Gonçalves, Cinara L., Ferreira, Gustavo C., Schuck, Patrícia F., Streck, Emilio L.
• Format: Article
• Language: English
• Subjects: Animals; Brain; Citrate (si)-Synthase - metabolism; Corpus Striatum - drug effects; Corpus Striatum - metabolism; Electron Transport Chain Complex Proteins - metabolism; Energic metabolism; Energy Metabolism - drug effects; Energy Metabolism - physiology; Hippocampus - drug effects; Hippocampus - metabolism; Infant rats; Malate Dehydrogenase - metabolism; Male; Metabolic Clearance Rate - drug effects; Rats; Rats, Wistar; Succinate Dehydrogenase - metabolism; Tissue Distribution - drug effects; Tyrosine; Tyrosine - pharmacology; Tyrosinemia type II
• ISSN: 0736-5748; 1873-474X
• DOI: 10.1016/j.ijdevneu.2013.03.005

•Acute administration of l-tyrosine inhibited the citrate synthase in striatum.•Acute administration of l-tyrosine inhibited the complexes I and II in striatum.•Administration of l-tyrosine increased the malate dehydrogenase in hippocampus.•Administration of l-tyrosine increased the succinate dehydrogenase in hippocampus.•Acute administration of l-tyrosine increased the complex II–III in hippocampus. Tyrosinemia type II is an inborn error of metabolism caused by mutations in the gene that encodes tyrosine aminotransferase, which leads to increased blood tyrosine levels. Considering that tyrosine levels are highly elevated in fluids of patients with tyrosinemia type II, and that previous studies demonstrated significant alterations in brain energy metabolism of young rats caused by l-tyrosine, the present study aimed to evaluate the effect of acute administration of l-tyrosine on the activities of citrate synthase, malate dehydrogenase, succinate dehydrogenase, and mitochondrial respiratory chain complexes I, II, II–III, and IV in posterior cortex, hippocampus, and striatum of infant rats. Wistar rats (10 days old) were killed 1h after a single intraperitoneal injection of tyrosine (500mg/kg) or saline. The activities of energy metabolism enzymes were evaluated in brain of rats. Our results demonstrated that acute administration of l-tyrosine inhibited the activity of citrate synthase activity in striatum and increased the activities of malate dehydrogenase and succinate dehydrogenase in hippocampus. On the other hand, these enzymes were not affected in posterior cortex. The activities of complex I and complex II were inhibited by acute administration of l-tyrosine in striatum. On the other hand, the acute administration of l-tyrosine increased the activity of activity of complex II–III in hippocampus. Complex IV was not affected by acute administration of l-tyrosine in infant rats. Our results indicate an alteration in the energy metabolism in hippocampus and striatum of infant rats after acute administration of l-tyrosine. If the same effects occur in the brain of the patients, it is possible that energy metabolism impairment may be contribute to possible damage in memory and cognitive processes in patients with tyrosinemia type II.