Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, USA.
Neuropharmacology. 2010 Jun;58(8):1246-51. doi: 10.1016/j.neuropharm.2010.03.006. Epub 2010 Mar 19.
The protein tyrosine kinase (PTK) inhibitor genistein has been widely used to examine potential effects of tyrosine phosphorylation on neurotransmitter function. We report here that genistein inhibits N-methyl-d-aspartate (NMDA) receptors through a direct effect. Whole-cell NMDA-activated current was recorded in native receptors from mouse hippocampal slice culture and rat recombinant NR1aNR2A and NR1aNR2B receptors transiently expressed in HEK293 cells. Extracellular application of genistein and NMDA reversibly inhibited NMDA-activated current. The inhibition of NMDA-activated current by genistein applied externally was not affected when genistein was also pre-equilibrated in the intracellular solution. Daidzein, an analog of genistein that does not block PTK, also inhibited NMDA-activated current. Coapplication of lavendustin A, a specific inhibitor of PTK, had no effect on the NMDA response. Moreover, genistein-induced inhibition of NMDA-activated current displayed concentration- and voltage-dependence. Our results demonstrate that genistein has a direct inhibitory effect on NMDA receptors that is not mediated via inhibition of tyrosine kinase. Thus, other PTK inhibitors may be more suitable for studying involvement of PTKs in NMDA receptor-mediated events.
蛋白酪氨酸激酶（PTK）抑制剂金雀异黄素被广泛用于研究酪氨酸磷酸化对神经递质功能的潜在影响。我们在此报告，金雀异黄素通过直接作用抑制 N-甲基-D-天冬氨酸（NMDA）受体。在原代培养的海马切片和瞬时表达于 HEK293 细胞的大鼠重组 NR1aNR2A 和 NR1aNR2B 受体中，记录全细胞 NMDA 激活电流。金雀异黄素和 NMDA 的细胞外应用可逆地抑制 NMDA 激活电流。当金雀异黄素也在细胞内液中预平衡时，金雀异黄素对外源性 NMDA 激活电流的抑制作用不受影响。金雀异黄素的类似物大豆黄素，不阻断 PTK，也抑制 NMDA 激活电流。特异性 PTK 抑制剂 lavendustin A 的共同应用对 NMDA 反应没有影响。此外，金雀异黄素诱导的 NMDA 激活电流抑制呈现浓度和电压依赖性。我们的结果表明，金雀异黄素对 NMDA 受体具有直接抑制作用，而不是通过抑制酪氨酸激酶介导的。因此，其他 PTK 抑制剂可能更适合研究 PTK 参与 NMDA 受体介导的事件。
