Encephalic photoreception and phototactic response in the troglobiont Somalian blind cavefish Phreatichthys andruzzii

Emma E. Tarttelin, Elena Frigato, James Bellingham, Viviana Di Rosa, Roberto Berti, Nicholas S. Foulkes, Robert J. Lucas, Cristiano Bertolucci

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Many physiological and behavioural responses to changes in environmental lighting conditions are mediated by extraocular photoreceptors. Here we investigate encephalic photoreception in Phreatichthys andruzzii, a typical cave-dwelling fish showing an extreme phenotype with complete anophthalmy and a reduction in size of associated brain structures. We firstly identified two P. andruzzii photopigments, orthologues of rod opsin and exo-rod opsin. In vitro, both opsins serve as light-absorbing photopigments with max around 500?nm when reconstituted with an A1 chromophore. When corrected for the summed absorption from the skin and skull, the spectral sensitivity profiles shifted to longer wavelengths (rod opsin: 521?nm; exo-rod opsin: 520?nm). We next explored the involvement of both opsins in the negative phototaxis reported for this species. A comparison of the spectral sensitivity of the photophobic response with the putative A2 absorbance spectra corrected for skin/skull absorbance indicates that the A2 versions of either or both of these pigments could explain the observed behavioural spectral sensitivity. © 2012. Published by The Company of Biologists Ltd.
    Original languageEnglish
    Pages (from-to)2898-2903
    Number of pages5
    JournalJournal of Experimental Biology
    Volume215
    Issue number16
    DOIs
    Publication statusPublished - Aug 2012

    Keywords

    • Cavefish
    • Exo-rod opsin
    • Extraretinal photoreception
    • Negative phototaxis
    • Rod opsin

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