ISSN:
1432-1351
Keywords:
Key words Rod-cone interaction
;
Scotopic spectral sensitivity
;
Cyprinid fish
;
Danio aequipinnatus
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003590050133
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