Institutes of Brain Science, Fudan University, Shanghai, China.
Brain Res. 2011 Sep 9;1411:1-8. doi: 10.1016/j.brainres.2011.07.008. Epub 2011 Jul 13.
Regulator of G-protein signaling (RGS) proteins 2 (RGS2) and 4 (RGS4) play an important role in regulating G(i/o)- and G(q)-coupled receptors. In the present study, we investigated the possible impact of RGS2 and RGS4 on modulation of glycine currents of rat retinal ganglion cells (RGCs) mediated by the G(i/o)-coupled melatonin MT(2) receptor, using immunohistochemistry, Western blot analysis and whole-cell patch-clamp techniques. By immunofluorescence labeling the expression profiles of RGS2 and RGS4 proteins were basically similar. Both of them were widely expressed in the rat retina, particularly in the inner plexiform layer (IPL) and the ganglion cell layer (GCL). In addition, sparse signals of RGS2 and RGS4 were also detected in the inner nuclear layer (INL). Double immunofluorescence labeling further showed that all of RGCs retrogradely labeled expressed both RGS2 and RGS4. Western blot analysis confirmed the presence of RGS2 and RGS4 proteins in the rat retina. Intracellular dialysis of RGCs with the antibody against RGS2/RGS4 to block RGS2/RGS4 function gradually increased glycine current amplitudes of these cells. In the presence of the RGS2/RGS4 antibody melatonin-induced potentiation of glycine currents of RGCs was not observable. These results suggest that RGS2/RGS4 are coupled to melatonin receptor signaling in rat RGCs and these proteins may regulate the MT(2) receptor to change melatonin-induced modulation of glycine currents in rat RGCs.
G 蛋白信号调节蛋白（RGS）2（RGS2）和 4（RGS4）在调节 G(i/o)-和 G(q)-偶联受体方面发挥着重要作用。在本研究中，我们使用免疫组织化学、Western blot 分析和全细胞膜片钳技术，研究了 RGS2 和 RGS4 对大鼠视网膜神经节细胞（RGCs）中由 G(i/o)-偶联褪黑素 MT(2)受体介导的甘氨酸电流调制的可能影响。通过免疫荧光标记，RGS2 和 RGS4 蛋白的表达谱基本相似。它们都广泛表达于大鼠视网膜中，特别是在内丛状层（IPL）和神经节细胞层（GCL）中。此外，在内核层（INL）中也检测到 RGS2 和 RGS4 的稀疏信号。双重免疫荧光标记进一步显示，所有 retrogradely 标记的 RGCs 都表达 RGS2 和 RGS4。Western blot 分析证实 RGS2 和 RGS4 蛋白存在于大鼠视网膜中。用针对 RGS2/RGS4 的抗体对 RGCs 进行细胞内透析以阻断 RGS2/RGS4 功能，逐渐增加了这些细胞的甘氨酸电流幅度。在存在 RGS2/RGS4 抗体的情况下，褪黑素不能诱导 RGCs 甘氨酸电流的增强。这些结果表明，RGS2/RGS4 与大鼠 RGCs 中的褪黑素受体信号相关联，这些蛋白可能调节 MT(2)受体，改变褪黑素诱导的大鼠 RGCs 中甘氨酸电流的调制。
