Assertion: retina's concentration | /r/CapableOf | open ion channels
Facets:
Source sentences:
text: Depolarization of rod cells (causing release of their neurotransmitter) occurs because in the dark, cells have a relatively high concentration of cyclic guanosine 3'-5' monophosphate (cGMP), which opens ion channels (largely sodium channels, though calcium can enter through these channels as well).