Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, PR China.
Ophthalmic Res. 2013;50(3):141-50. doi: 10.1159/000351639. Epub 2013 Aug 15.
To study the electrophysiological properties of the light-evoked currents in ganglion cells in situations of retinal degeneration.
We investigated light-evoked currents in ganglion cells by performing whole-cell patch-clamp recordings from ganglion cells using a retina-stretched preparation from Royal College of Surgeons (RCS) rats, a model of retinal degeneration and congenic controls at different ages. Pharmacological inhibitors of the AMPA receptor (NBQX), GABA receptor (BMI), and sodium channels (TTX) were used to identify the components of the light-evoked currents in ON, OFF and ON-OFF retinal ganglion cells.
We found that the light-evoked currents in ganglion cells from control rats were inhibited by NBQX, BMI and TTX, suggesting that AMPA receptors, GABA receptors and sodium channels contribute to these currents in ganglion cells. However, only AMPA receptor-mediated currents were recorded in RCS rats. Light-evoked inward currents were absent in the majority of ganglion cells from RCS rats, particularly at the later stages of retinal degeneration. At earlier stages of retinal degeneration, we found that both the timing and amplitude of light-evoked currents are significantly different in ganglion cells from RCS and control rats.
Our study furthers the understanding of the electrophysiological characteristics of retinal ganglion cells during retinal degeneration, and provides insight into the optimal timing for the treatment of retinal degeneration.
研究视网膜变性情况下，光激电流在神经节细胞中的电生理特性。
我们通过对皇家外科学院（RCS）大鼠视网膜伸展标本中的神经节细胞进行全细胞膜片钳记录，研究了光激电流。RCS 大鼠是视网膜变性的模型，我们还对不同年龄的同系对照鼠进行了研究。我们使用 AMPA 受体（NBQX）、GABA 受体（BMI）和钠通道（TTX）的药理学抑制剂来鉴定 ON、OFF 和 ON-OFF 视网膜神经节细胞中光激电流的成分。
我们发现，来自对照鼠的神经节细胞的光激电流被 NBQX、BMI 和 TTX 抑制，这表明 AMPA 受体、GABA 受体和钠通道都对神经节细胞中的这些电流有贡献。然而，在 RCS 大鼠中仅记录到 AMPA 受体介导的电流。在 RCS 大鼠的大多数神经节细胞中，光激内向电流缺失，特别是在视网膜变性的晚期。在视网膜变性的早期阶段，我们发现 RCS 和对照鼠的神经节细胞中的光激电流的定时和幅度都有显著差异。
我们的研究进一步了解了视网膜变性过程中神经节细胞的电生理特征，并为视网膜变性的治疗提供了最佳时机的深入了解。
