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Updated: Aug 15, 2026

Light Preference Assay to Study Innate and Circadian Regulated Photobehavior in Drosophila Larvae
Published on: April 20, 2013
Two realms of dark adaptation
M L Firsov1, A V Kolesnikov, E Yu Golobokova
1Institute for Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez Prospect, 194223 St. Petersburg, Russia.
Abstract:
The recovery of rod responsiveness after saturating flashes is greatly retarded above a certain critical level of rhodopsin bleaching (approximately 0.1%). A mathematical description of the process of turn-off of the phototransduction cascade allows attributing different phases of the recovery to specific products of rhodopsin photolysis. The fast phase is determined by quenching of metarhodopsin II and activated transducin. The slow phase is controlled by decay of partially inactivated (phosphorylated and arrestin-bound) metarhodopsins, and by regeneration of rhodopsin. The transition between the two regimes of adaptation is rather abrupt, occurring within a few-fold range of stimulus intensity. This marks the border between reversal of light adaptation and dark adaptation, as it is commonly defined.
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