Sodium channels in transient retinal bipolar cells enhance visual responses in ganglion cells

Tomomi Ichinose, Colleen R. Shields, Peter D. Lukasiewicz

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

Retinal bipolar cells are slow potential neurons that respond to photoreceptor inputs with graded potentials and do not fire action potentials. We found that transient ON bipolar cells recorded in retinal slices possess voltage-gated sodium channels located on either their dendrites or somas. The sodium currents in these neurons did not generate spikes but enhanced voltage responses evoked by visual stimulation, which selectively boosted transmission to transient ganglion cells. In contrast, sodium currents were not found in sustained ON bipolar cells, and light responses in sustained bipolar cells and ganglion cells were not affected by TTX. The presence of sodium channels in transient ON bipolar cells contributed to the separation of transient and sustained signals by selectively enhancing the responses of ON transient ganglion cells to light. Our results suggest that bipolar cell sodium channels augment transient signals and contribute to the temporal segregation of visual information.

Original languageEnglish
Pages (from-to)1856-1865
Number of pages10
JournalJournal of Neuroscience
Volume25
Issue number7
DOIs
StatePublished - Feb 16 2005

Keywords

  • EPSC
  • EPSP
  • Glutamate receptor
  • Patch clamp
  • Retina
  • Retinal ganglion cell
  • Sodium channel

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