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 language | English |
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Pages (from-to) | 4360-4371 |
Number of pages | 12 |
Journal | Journal of Neuroscience |
Volume | 32 |
Issue number | 13 |
DOIs | |
State | Published - Mar 28 2012 |