Laboratório de Bioenergética, Programa de, Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, SC, 88806-000, Brazil.
Neurochem Res. 2013 Aug;38(8):1742-6. doi: 10.1007/s11064-013-1078-0. Epub 2013 May 21.
Most inborn errors of tyrosine catabolism produce hypertyrosinemia. Neurological manifestations are variable and some patients are developmentally normal, while others show different degrees of developmental retardation. Considering that current data do not eliminate the possibility that elevated levels of tyrosine and/or its derivatives may have noxious effects on central nervous system development in some patients, the present study evaluated nerve growth factor (NGF) levels in hippocampus, striatum and posterior cortex of young rats. In our acute protocol, Wistar rats (10 and 30 days old) were killed 1 h after a single intraperitoneal administration of L-tyrosine (500 mg/kg) or saline. Chronic administration consisted of L-tyrosine (500 mg/kg) or saline injections 12 h apart for 24 days in Wistar rats (7 days old); the rats were killed 12 h after the last injection. NGF levels were then evaluated. Our findings showed that acute administration of L-tyrosine decreased NGF levels in striatum of 10-day-old rats. In the 30-day-old rats, NGF levels were decreased in hippocampus and posterior cortex. On the other hand, chronic administration of L-tyrosine increased NGF levels in posterior cortex. Decreased NGF may impair growth, differentiation, survival and maintenance of neurons.
大多数酪氨酸分解代谢的先天性错误会导致高酪氨酸血症。神经表现是多变的，一些患者发育正常，而另一些则表现出不同程度的发育迟缓。考虑到目前的数据不能排除在某些患者中，升高的酪氨酸及其衍生物水平可能对中枢神经系统发育有有害影响的可能性，本研究评估了神经生长因子（NGF）在幼年大鼠海马体、纹状体和后皮质中的水平。在我们的急性方案中，Wistar 大鼠（10 天和 30 天）在单次腹腔内给予 L-酪氨酸（500mg/kg）或生理盐水后 1 小时被处死。慢性给药包括 Wistar 大鼠（7 天大）每隔 12 小时给予 L-酪氨酸（500mg/kg）或生理盐水注射，共 24 天；最后一次注射后 12 小时处死大鼠。然后评估 NGF 水平。我们的研究结果表明，急性给予 L-酪氨酸可降低 10 天大鼠纹状体中的 NGF 水平。在 30 天大的大鼠中，海马体和后皮质中的 NGF 水平降低。另一方面，L-酪氨酸的慢性给药可增加后皮质中的 NGF 水平。NGF 的减少可能会损害神经元的生长、分化、存活和维持。
