Electrical interactions between photoreceptors in the compound eye of Periplaneta americana [RESEARCH ARTICLE]

Paulus Saari, Esa-Ville Immonen, Andrew S. French, Päivi H. Torkkeli, Hongxia Liu, Kyösti Heimonen, and Roman V. Frolov 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...
Source: Journal of Experimental Biology - Category: Biology Authors: Tags: RESEARCH ARTICLE Source Type: research