Ambient light regulates sodium channel activity to dynamically control retinal signaling

Tomomi Ichinose, Peter D. Lukasiewicz

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


The retinal network increases its sensitivity in low-light conditions to detect small visual inputs and decreases its sensitivity in bright-light conditions to prevent saturation. However, the cellular mechanisms that adjust visual signaling in the retinal network are not known. Here, we show that voltage-gated sodium channels in bipolar cells dynamically control retinal light sensitivity. In dim conditions, sodium channels amplified light-evoked synaptic responses mediated by cone pathways. Conversely, in bright conditions, sodium channels were inactivated by dopamine released from amacrine cells, and they did not amplify synaptic inputs, minimizing signal saturation. Our findings demonstrate that bipolar cell sodium channels mediate light adaptation by controlling retinal signaling gain.

Original languageEnglish
Pages (from-to)4756-4764
Number of pages9
JournalJournal of Neuroscience
Issue number17
StatePublished - Apr 25 2007


  • Bipolar cell
  • Dopamine
  • Ganglion cell
  • Patch clamp
  • Retinal network adaptation
  • Sodium channel


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