title: Extraction (DSX) from Erigeron breviscapus modulates outward potassium currents in rat retinal ganglion cells.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Key Laboratory for Visual Function and Ophthalmopathy, Chengdu University of Traditional Chinese Medicine, Chengdu 610032, Sichuan Province, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Yin
authors.affiliation: Institutes of Brain Science, Fudan University, Shanghai 200032, China.
authors.forename: Zhong-Feng
authors.initials: ZF
authors.lastname: Wang
authors.affiliation: Key Laboratory for Visual Function and Ophthalmopathy, Chengdu University of Traditional Chinese Medicine, Chengdu 610032, Sichuan Province, China.
authors.forename: Jun-Guo
authors.initials: JG
authors.lastname: Duan
authors.affiliation: Key Laboratory for Visual Function and Ophthalmopathy, Chengdu University of Traditional Chinese Medicine, Chengdu 610032, Sichuan Province, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Ji
authors.affiliation: Key Laboratory for Visual Function and Ophthalmopathy, Chengdu University of Traditional Chinese Medicine, Chengdu 610032, Sichuan Province, China.
authors.forename: Xue-Jing
authors.initials: XJ
authors.lastname: Lu
keywords: Erigeron breviscapus; potassium channel; retinal ganglion cells