RT Journal Article
SR Electronic
T1 Ambient Light Regulates Sodium Channel Activity to Dynamically Control Retinal Signaling
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 4756
OP 4764
DO 10.1523/JNEUROSCI.0183-07.2007
VO 27
IS 17
A1 Tomomi Ichinose
A1 Peter D. Lukasiewicz
YR 2007
UL http://www.jneurosci.org/content/27/17/4756.abstract
AB 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.