Yin Shuo, Wang Zhong-Feng, Duan Jun-Guo, Ji Lu, Lu Xue-Jing
Key Laboratory for Visual Function and Ophthalmopathy, Chengdu University of Traditional Chinese Medicine, Chengdu 610032, Sichuan Province, China.
Institutes of Brain Science, Fudan University, Shanghai 200032, China.
Int J Ophthalmol. 2015 Dec 18;8(6):1101-6. doi: 10.3980/j.issn.2222-3959.2015.06.04. eCollection 2015.
To investigate the effect of DSX, an active component extracted from Erigeron breviscapus, on the voltage-gated outward K(+) channel currents in rat retinal ganglion cells (RGCs) by using electrophysiological method, and to explore the possible mechanisms of DSX on optic nerve protection.
Outward K(+) currents were recorded by using whole-cell patch-clamp techniques on acutely isolated rat RGCs. Outward K(+) currents were induced by a series of depolarizing voltage pulses from a holding potential of -70 mV to +20 mV in an increment of 10 mV.
Extracellular application of DSX voltage-dependently suppressed both the steady-state and peak current amplitudes of outward K(+) currents in rat RGCs. Furthermore, DSX reversibly and dose-dependently inhibited the amplitudes of outward K(+) currents of the cells. At +20 mV membrane potential DSX at the concentrations of 0.02 g/L and 0.05 g/L showed no significant effects on the currents. In contrast, DSX at higher concentrations (0.1 g/L, 0.2 g/L and 0.5 g/L) significantly suppressed the current amplitudes.
These results suggest that DSX reversibly and dose-dependently suppress outward K(+) channel currents in rat RGCs, which may be one of the possible mechanisms underlying Erigeron breviscapus prevents vision loss and RGC damage caused by glaucoma.
采用电生理方法研究灯盏花中提取的活性成分灯盏细辛素（DSX）对大鼠视网膜神经节细胞（RGCs）电压门控外向钾离子通道电流的影响，并探讨DSX对视神经保护的可能机制。
采用全细胞膜片钳技术记录急性分离的大鼠RGCs的外向钾离子电流。通过从-70 mV的钳制电位以10 mV的增量到+20 mV的一系列去极化电压脉冲诱导外向钾离子电流。
细胞外应用DSX电压依赖性地抑制大鼠RGCs外向钾离子电流的稳态和峰值电流幅度。此外，DSX可逆且剂量依赖性地抑制细胞外向钾离子电流的幅度。在膜电位为+20 mV时，0.02 g/L和0.05 g/L浓度的DSX对电流无显著影响。相比之下，较高浓度（0.1 g/L、0.2 g/L和0.5 g/L）的DSX显著抑制电流幅度。
这些结果表明，DSX可逆且剂量依赖性地抑制大鼠RGCs外向钾离子通道电流，这可能是灯盏花预防青光眼导致的视力丧失和RGC损伤的可能机制之一。
