title: Performance of blue- and green-sensitive photoreceptors of the cricket Gryllus bimaculatus.
abstract: The compound eye of the cricket Gryllus bimaculatus contains a specialized dorsal rim area (DRA) populated by distinct blue-sensitive photoreceptors responsible for perception of polarized light. The rest of the eye is dominated by green-sensitive photoreceptors. Using patch clamp we studied dissociated ommatidia of nocturnal adults and diurnal eight-instar nymphs with the goals (1) of characterizing the biophysical properties of cricket photoreceptors in general and (2) describing the functionally dissimilar blue- and green-sensitive photoreceptors in terms of voltage-gated channel composition and signal coding. Despite different lifestyles, adult and nymph photoreceptors were indistinguishable. No significant circadian changes were observed in K⁺ currents. In contrast, prominent differences were seen between blue- and green-sensitive photoreceptors. The former were characterized by relatively low absolute sensitivity, high input resistance, slow quantum bumps with long latencies, small light-induced and K⁺ currents and low steady-state depolarization. Information rate, a measure of photoreceptor performance calculated from voltage responses to bandwidth-limited white noise-modulated light contrast, was 87 ± 8 bits s⁻¹ in green-sensitive photoreceptors vs. 59 ± 14 bits s⁻¹ in blue-sensitive photoreceptors, implying a limited role of DRA in the perception of visual contrasts. In addition, evidence of electrical coupling between photoreceptors is presented.
authors.affiliation: Division of Biophysics, Department of Physics, University of Oulu, PO BOX 3000, 90014, Oulu, Finland, roman.frolov@oulu.fi.
authors.forename: Roman V
authors.initials: RV
authors.lastname: Frolov
authors.forename: Esa-Ville
authors.initials: EV
authors.lastname: Immonen
authors.forename: Matti
authors.initials: M
authors.lastname: Weckström
mesh_terms: D000818:Animals; D001703:Biophysics; D003116:Color; D003118:Color Perception / Q000502:physiology*; D004558:Electric Stimulation; D006135:Gryllidae / Q000033:anatomy & histology* / Q000502:physiology; D008027:Light; D008564:Membrane Potentials / Q000502:physiology; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D011930:Reaction Time; D013057:Spectrum Analysis
chemical_list: D011188:Potassium