The mode of retinal presynaptic inhibition switches with light intensity

Tomomi Ichinose, Peter D. Lukasiewicz

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Excitatory amino acid transporters (EAATs) terminate signaling in the CNS by clearing released glutamate. Glutamate also evokes an EAAT-mediated Cl - current, but its role in CNS signaling is poorly understood. We show in mouse retina that EAAT-mediated Cl - currents that were evoked by light inhibit rod pathway signaling. EAATs reside on rod bipolar cell axon terminals where GABA and glycine receptors also mediate light-evoked inhibition. We found that the mode of inhibition depended on light intensity. Dim light evoked GABAergic and glycinergic inhibition with rapid kinetics and a large spatial extent. Bright light evoked predominantly EAATmediated inhibition with slow kinetics and a small spatial extent. The switch to EAAT-mediated signaling in bright light supplements receptor-mediated signaling to expand the dynamic range of inhibition and contributes to the transition from rod to cone signaling by suppressing rod pathway signaling in bright light conditions.

Original languageEnglish
Pages (from-to)4360-4371
Number of pages12
JournalJournal of Neuroscience
Volume32
Issue number13
DOIs
StatePublished - Mar 28 2012

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