Intracerebroventricular Injection of L-Alanine Induces a Sedative Effect under an Acute Stressful Condition in Neonatal Chicks

Pyruvate can be synthesized from amino acids such as L-alanine, L-serine and L-cysteine. Recently, we reported that intracerebroventricular (i.c.v.) injection of L-serine and L-cysteine attenuated acute stress in chicks. This fact implies that amino acid substrates for pyruvate play a sedative role in the brain. However, no information was available for L-alanine. To elucidate the central effect of L-alanine on stress responses, L-alanine (0.8μmol) or saline was administered i.c.v. just before exposure to social separation stress. The social separation stress increased spontaneous activity and vocalization of chicks, but these responses were attenuated by the i.c.v. injection of L-alanine. In conclusion, in addition to L-serine and L-cysteine, centrally administered L-alanine may be effective in attenuating anxiety induced by a psychological stressor.