Exercício aeróbico agudo restaura a concentração de triptofano em cérebro de ratos com hiperfenilalaninemia

Abstract

Introduction: Phenylketonuria (PKU) is characterized by deficiency of the enzyme phenylalanine hydroxylase, leading to accumulation of phenylalanine. Early diagnosis and subordination to low--phenylalanine diet are important to prevent the harmful effects of hyperphenylalaninemia. In case the diet is not strictly followed, some possible effects are imbalance in the neutral amino acids that use the same carrier of phenylalanine to cross the blood-brain barrier, causing hence reduction in tryptophan entry, the precursor of serotonin in the brain. This neurotransmitter has been implicated in the regulation of mood states, and its high production is linked to central fatigue in individuals subjected to prolonged exercise. Physical exercise increases free tryptophan levels in the blood, which facilitates its influx in the brain, and therefore, may be useful in hyperphenylalaninemia states. Objective: To assess whether aerobic exercise is able to normalize the concentrations of tryptophan in the brain of rats with hyperphenylalaninemia. Methods: 32 rats were randomly assigned to sedentary (Sed) and exercise (Exe) groups, and then divided into control (SAL) and hyperphenylalaninemia (PKU). Hyperphenylalaninemia was induced by administration of alpha-metylphenylalanine and phenylalanine for three days, while the SAL groups received saline. Exe groups held a session of aerobic exercise lasting 60 minutes and speed of 12 m.min -1 . Results: The concentration of tryptophan in the brain of PKU groups was significantly lower than SAL groups (both in Sed and Exe groups), compatible with the condition of hyperphenylalaninemia. The exercise increased brain tryptophan levels comparing to sedentary animals. The most interesting finding was that the brain tryptophan levels of ExePKU group were not different from SedSAL group. Conclusion: The results indicate an important role of aerobic exercise to restore the concentration of tryptophan in the brain in hyperphenylalaninemic rats.

Efeitos agudos de diferentes intensidades e volumes de exercício aeróbio sobre as concentrações de triptofano e serotonina em mulheres idosas fisicamente ativas

“…Apesar de estudos [12][13][14] apontarem o exercício físico, tanto agudo como crônico, como um interessante método alternativo para aumentar as concentrações de serotonina e seu precursor (triptofano), não é do nosso conhecimento estudos que tenham investigado os efeitos de diferentes intensidades e volumes de exercício aeróbio agudo sobre as concentrações de serotonina e triptofano em mulheres idosas, mesmo sendo essa população (idosos) frequentemente atingida por depressão [9][10][11] e, conhecidamente essa desordem estar associada às concentrações do neurotransmissor serotonina e seu precursor [4][5][6] , o que por si, justi ca a presente investigação.…”

“…Desta forma, investigações apontam haver uma maior prevalência de sintomas de depressão na população idosa quando comparado a indivíduos jovens [9][10][11] . Entretanto, recentes estudos longitudinais e transversais, em adultos jovens 12 e em ratos 13 ,…”