Medical Definition of Dark current
1.
Current caused by constant influx of sodium ions into the rod outer segment of retinal photoreceptors and that is blocked by light (leading to hyperpolarization).
The plasma membrane sodium channel is controlled through a cascade of amplification reactions initiated by photon capture by rhodopsin in the disc membrane.
This entry appears with permission from the Dictionary of Cell and Molecular Biology
(11 Mar 2008)
Lexicographical Neighbors of Dark Current
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