Simon J R, Bare D J, Ghetti B, Richter J A
Department of Psychiatry, Indiana University School of Medicine, Indianapolis 46202, USA.
Neurosci Lett. 1997 Mar 21;224(3):201-5. doi: 10.1016/S0304-3940(97)13479-6.
The present investigation was undertaken to test the hypothesis that a reduction in the activity of protein tyrosine kinases would result in an alteration in dopamine transport. Genistein, a broad-spectrum inhibitor of protein tyrosine kinases, inhibited dopamine uptake into mouse striatal homogenates with an IC50 of 18 microM. The inhibition by genistein was rapid, reversible and somewhat selective, in that genistein did not inhibit the uptake of choline or GABA under similar conditions. Kinetic analyses indicated that genistein was a non-competitive inhibitor. Another protein tyrosine kinase inhibitor, tyrphostin 23, also inhibited transport but was significantly less potent than genistein. Tyrphostin 25 and lavendustin A were without major effect on dopamine uptake. In addition, the inactive structural analog of genistein, genistein, had no significant effect on dopamine uptake. The inhibition of dopamine transport by 50 microM genistein was accompanied by a reduction in the level of a 110-kDa band of tyrosine phosphoprotein. It is suggested that protein tyrosine kinases play a role in the cascade of events which ultimately lead to regulation of neuronal dopamine transport.
本研究旨在验证蛋白质酪氨酸激酶活性降低会导致多巴胺转运改变这一假说。染料木黄酮是一种蛋白质酪氨酸激酶的广谱抑制剂，它抑制小鼠纹状体匀浆对多巴胺的摄取，半数抑制浓度（IC50）为18微摩尔。染料木黄酮的抑制作用迅速、可逆且具有一定选择性，即在相似条件下它不抑制胆碱或γ-氨基丁酸（GABA）的摄取。动力学分析表明染料木黄酮是一种非竞争性抑制剂。另一种蛋白质酪氨酸激酶抑制剂 tyrphostin 23 也抑制转运，但效力明显低于染料木黄酮。Tyrphostin 25 和薰衣草霉素 A 对多巴胺摄取无主要影响。此外，染料木黄酮的无活性结构类似物对多巴胺摄取无显著影响。50微摩尔染料木黄酮对多巴胺转运的抑制伴随着一条110 kDa酪氨酸磷酸化蛋白条带水平的降低。提示蛋白质酪氨酸激酶在最终导致神经元多巴胺转运调节的一系列事件中起作用。
