Photoreceptor responses of fruitflies with normal and reduced arrestin content studied by simultaneous measurements of visual pigment fluorescence and ERG

• DOI: 10.1007/s00359-009-0489-5
• Publication Date: 2009-11-18T07:13:36Z
• Authors: Gregor Belušič; Primož Pirih; Doekele G. Stavenga
• Keywords: Arrestin; Wild type; Erg; Electroretinography; Stimulus (psychology); Visual phototransduction

We have simultaneously measured the electroretinogram (ERG) and metarhodopsin content via fluorescence in white-eyed, wild-type Drosophila arrestin2 hypomorphic mutant (w − ;arr2 3 ) at a range of stimulus wavelengths intensities. Photoreceptor response amplitude termination (transition between full repolarization prolonged depolarizing afterpotential, PDA) were related to visual pigment conversions arrestin concentration. The data implemented kinetic model rhodopsin–arrestin cycle, allowing us estimate active concentration as function effective light intensity Arrestin reduction modestly increased sensitivity decreased photoreceptor dynamic range. Compared wild type, transition PDA occurred lower fraction was more abrupt. developed steady-state stochastic interpret dependence on help deduce rhodopsin ratio from data. feasibility different experimental methods for estimation ERG is discussed.