University of Oulu

Saari, P., Immonen, E., French, A., Torkkeli, P., Liu, H., Heimonen, K., Frolov, R. (2018) Electrical interactions between photoreceptors in the compound eye of Periplaneta americana. Journal of Experimental Biology, 221 (21), jeb189340. doi:10.1242/jeb.189340

Electrical interactions between photoreceptors in the compound eye of Periplaneta americana

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Author: Saari, Paulus1; Immonen, Esa-Ville1; French, Andrew S.2;
Organizations: 1Biophysics group, Nano and Molecular Systems Research Unit, University of Oulu
2Department of Physiology and Biophysics, Dalhousie University
Format: article
Version: accepted version
Access: embargoed
Persistent link: http://urn.fi/urn:nbn:fi-fe201901162255
Language: English
Published: Company of Biologists, 2018
Publish Date: 2019-11-01
Description:

Abstract

The compound eye of Periplaneta americana contains two spectral classes of photoreceptors: narrow-band UV-sensitive and broad-band green-sensitive. In intracellular recordings, stimulation of green-sensitive photoreceptors with flashes of relatively bright UV/violet light produced anomalous delayed depolarization after the end of the normal light response, whereas stimulation of UV-sensitive photoreceptors with green light elicited biphasic responses characterized by initial transient hyperpolarization followed by prolonged delayed depolarization. To explore the basis for these findings, we used RNA interference to selectively suppress expression of the genes encoding green opsin (GO1), UV opsin (UVO) or both. The hyperpolarizing component in UV-sensitive photoreceptors was eliminated and the delayed depolarization was reduced after GO1 knockdown, suggesting that the hyperpolarization represents fast inhibitory interactions between green- and UV-sensitive photoreceptors. Green-sensitive photoreceptor responses of GO1 knockdowns to flashes of UV/violet were almost exclusively biphasic, whereas residual responses to green had normal kinetics. Knockdown of UVO reduced the responses of UV-sensitive photoreceptors but had minor effects on delayed depolarization in green-sensitive photoreceptors. Angular sensitivity analysis indicated that delayed depolarization of green-sensitive photoreceptors by violet light originates from excitation of (an)other photoreceptor(s) in the same ommatidium. The angle at which the maximal delayed depolarization was observed in green-sensitive photoreceptors stimulated with violet light did not match the angle of the maximal transient depolarization. In contrast, no significant mismatch was observed for delayed depolarization elicited by green light. These results suggest that the cellular sources of the normal transient and additional delayed depolarization by violet light are separate and distinct.

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Series: Journal of experimental biology
ISSN: 0022-0949
ISSN-E: 1477-9145
ISSN-L: 0022-0949
Volume: 221
Article number: jeb189340
DOI: 10.1242/jeb.189340
OADOI: https://oadoi.org/10.1242/jeb.189340
Type of Publication: A1 Journal article – refereed
Field of Science: 217 Medical engineering
3111 Biomedicine
Subjects:
Funding: This research was funded by the Natural Sciences and Engineering Research Council of Canada (RGPIN/05565 to P.T. and RGPIN/03712 to A.S.F.).
Copyright information: © 2018 The Authors. Published by The Company of Biologists Ltd.