Changes in electrophysiological properties of photoreceptors in Periplaneta americana associated with the loss of screening pigment
|Author:||Saari, Paulus1; Immonen, Esa‑Ville1; Kemppainen, Joni1;|
1Biophysics Group, Nano and Molecular Systems Research Unit, University of Oulu, Oulu, Finland
2Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez Pr., Saint Petersburg 194223, Russia
3Department of Physiology and Biophysics, Dalhousie University, P.O. Box 15000, Halifax, NS B3H 4R2, Canada
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe201901253002
|Publish Date:|| 2019-09-20
Absence of screening pigment in insect compound eyes has been linked to visual dysfunction. We investigated how its loss in a white-eyed mutant (W-E) alters the photoreceptor electrophysiological properties, opsin gene expression, and the behavior of the cockroach, Periplaneta americana. Whole-cell patch-clamp recordings of green-sensitive photoreceptors in W-E cockroaches gave reduced membrane capacitance, absolute sensitivity to light, and light-induced currents. Decreased low-pass filtering increased voltage-bump amplitudes in W-E photoreceptors. Intracellular recordings showed that angular sensitivity of W-E photoreceptors had two distinct components: a large narrow component with the same acceptance angle as wild type, plus a relatively small wide component. Information processing was evaluated using Gaussian white-noise modulated light stimulation. In bright light, W-E photoreceptors demonstrated higher signal gain and signal power than wild-type photoreceptors. Expression levels of the primary UV- and green-sensitive opsins were lower and the secondary green-sensitive opsin significantly higher in W-E than in wild-type retinae. In behavioral experiments, W-E cockroaches were significantly less active in dim green light, consistent with the relatively low light sensitivity of their photoreceptors. Overall, these differences can be related to the loss of screening pigment function and to a compensatory decrease in the rhabdomere size in W-E retinae.
Journal of comparative physiology. A
|Pages:||915 - 928|
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
1182 Biochemistry, cell and molecular biology
1184 Genetics, developmental biology, physiology
The work was supported by State budget grant of Russian Federation #АААА-А18-118013090245-6 to MZ and Natural Sciences and Engineering Research Council of Canada (NSERC) Grants RGPIN/05565 (to P. H. Torkkeli) and RGPIN/03712 (to A. S. French).
© Springer-Verlag GmbH Germany, part of Springer Nature 2018. This is a post-peer-review, pre-copyedit version of an article published in J Comp Physiol A.
The final authenticated version is available online at: https://doi.org/10.1007/s00359-018-1290-0.