Effects of 3-acetylpyridine on the levels of several amino acids in different CNS regions of the rat

The effects of one intraperitoneal injection of 60–65 mg/kg of 3-acetylpyridine (3-AP) on the levels of aspartate, glutamate, GABA, taurine, glycine, and alanine in the cerebellum, medulla, telencephalon, and diencephalon-mesencephalon of the rat were studied at various times (4–28 days) after injection. In the first 4–7 days, the levels of glutamate, GABA, glycine, and alanine in the cerebellum were 10–30% higher in the 3-AP-treated rats than in the control animals. By day 14, the levels of these four amino acids were normal (in the case of glutamate and glycine) or below normal (for GABA and alanine). By day 21, the values for GABA and alanine returned to normal. In the first 7 days, the level of aspartate in the cerebellum was the same in both the 3-AP- and saline-injected groups. From days 14 to 28, the level of aspartate in the cerebellum was 10–20% lower in the 3-AP-injected group than in the saline-treated animals. The level of taurine in the cerebellum was 15–30% lower in the 3-AP group than in the control group from days 7 to 28. The pattern of changes observed in the medulla in the first 7 days was similar to that found in the cerebellum for this period. However, unlike the data for the cerebellum, the level of aspartate in the medulla was unchanged by the 3-AP injection from day 14 to day 28, and the level of glutamate in the medulla remained higher (10–15%) from days 14 to 28 in the 3-AP-injected animals with respect to control values. The levels of taurine in the medulla were lower (10–15%) from day 7 to day 28 in the 3-AP injected group with respect to control values. The injection of 3-AP did not alter the levels of aspartate, glutamate, GABA, taurine, glycine, or alanine in the telencephalon on days 7, 14, 21, or 28 and in the diencephalon-mesencephalon on day 21 with respect to control levels.