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Journal of Comparative Physiology A

, Volume 181, Issue 5, pp 493–500 | Cite as

Activity of long-wavelength cones under scotopic conditions in the cyprinid fish Danio aequipinnatus

  • P. van Roessel
  • A. G. Palacios
  • T. H. Goldsmith
ORIGINAL PAPER

Abstract

In carp (Cyprinus) and goldfish (Carassius), long-wavelength cones are reported to be active under scotopic conditions. Using the electroretinogram (ERG), we tested another cyprinid fish, Danio aequipinnatus, which contains A1-based visual pigments and for which we had previously measured the spectral sensitivities of individual cones. Dark adaptation curves show a rod/cone break at about 45 min. When thoroughly dark-adapted, the spectral sensitivity function is broader than can be accounted for by self-screening of rhodopsin, but it can be modeled by an additive combination of rods and the 560-nm cones. Dim, red background light causes adaptation of rods and a broadening of the spectral sensitivity function, which can be simulated by increasing the proportion of cones in the model. Brighter red backgrounds adapt the 560-nm cones. Because of the effect of red adapting lights, the ERG evidence for the participation of long-wavelength cones close to visual threshold appears to be different in Danio than in the goldfish Carassius.

Key words Rod-cone interaction Scotopic spectral sensitivity Cyprinid fish Danio aequipinnatus 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • P. van Roessel
    • 1
  • A. G. Palacios
    • 1
  • T. H. Goldsmith
    • 1
  1. 1.Department of Molecular, Cellular, and Developmental Biology, Yale University, P.O. Box 208103, New Haven, CT 06520-8103, USA Tel.: +1-203 432-3494; Fax: +1-203 432-6161 e-mail: timothy.goldsmith@yale.eduUS

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