University of Oulu

Frolov, R., Immonen, E., Saari, P., Torkkeli, P., Liu, H., French, A. (2018) Phenotypic plasticity in Periplaneta americana photoreceptors. Journal of General Physiology, 150(10), 1386-1396. doi:10.1085/jgp.201812107

Phenotypic plasticity in Periplaneta americana photoreceptors

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Author: Frolov, Roman V.1; Immonen, Esa-Ville1; Saari, Paulus1;
Organizations: 1Biophysics group, Nano and Molecular Systems Research Unit, University of Oulu
2Department of Physiology and Biophysics, Dalhousie University
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.9 MB)
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Language: English
Published: Rockefeller University Press, 2018
Publish Date: 2019-01-15


Plasticity is a crucial aspect of neuronal physiology essential for proper development and continuous functional optimization of neurons and neural circuits. Despite extensive studies of different visual systems, little is known about plasticity in mature microvillar photoreceptors. Here we investigate changes in electrophysiological properties and gene expression in photoreceptors of the adult cockroach, Periplaneta americana, after exposure to constant light (CL) or constant dark (CD) for several months. After CL, we observed a decrease in mean whole-cell capacitance, a proxy for cell membrane area, from 362 ± 160 to 157 ± 58 pF, and a decrease in absolute sensitivity. However, after CD, we observed an increase in capacitance to 561 ± 155 pF and an increase in absolute sensitivity. Small changes in the expression of light-sensitive channels and signaling molecules were detected in CD retinas, together with a substantial increase in the expression of the primary green-sensitive opsin (GO1). Accordingly, light-induced currents became larger in CD photoreceptors. Even though normal levels of GO1 expression were retained in CL photoreceptors, light-induced currents became much smaller, suggesting that factors other than opsin are involved. Latency of phototransduction also decreased significantly in CL photoreceptors. Sustained voltage-activated K+ conductance was not significantly different between the experimental groups. The reduced capacitance of CL photoreceptors expanded their bandwidth, increasing the light-driven voltage signal at high frequencies. However, voltage noise was also amplified, probably because of unaltered expression of TRPL channels. Consequently, information transfer rates were lower in CL than in control or CD photoreceptors. These changes in whole-cell capacitance and electrophysiological parameters suggest that structural modifications can occur in the photoreceptors to adapt their function to altered environmental conditions. The opposing patterns of modifications in CL and CD photoreceptors differ profoundly from previous findings in Drosophila melanogaster photoreceptors.

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Series: The journal of general physiology
ISSN: 0022-1295
ISSN-E: 1540-7748
ISSN-L: 0022-1295
Volume: 150
Issue: 10
Pages: 1386 - 1396
DOI: 10.1085/jgp.201812107
Type of Publication: A1 Journal article – refereed
Field of Science: 1184 Genetics, developmental biology, physiology
Funding: This research was supported by the Natural Sciences and Engineering Research Council of Canada grants RGPIN/5565 (to P.H. Torkkeli) and RGPIN/03712 (to A.S. French).
Copyright information: © 2018 Frolov et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 International license, as described at