Abstract
Abstract: :
Purpose: The zebrafish (Danio rerio) has been shown to be a useful model for examining the effects of lighting environments on visual processing. Past studies have shown that abnormal lighting conditions, such as constant white light and constant darkness, have an adverse effect on both visual behavior and physiology. The purpose of this study was to determine whether the development of the cone contributions to the electroretinogram (ERG) response could be selectively altered by rearing zebrafish under abnormal lighting conditions that consisted of only narrow portions of the spectrum. Methods: Zebrafish reared in restricted rearing conditions were exposed to either constant 'blue' LED lights (450 nm peak; BB), or 'green' LED lights (540 nm peak; GG) from fertilization to up to 10 days postfertilization. Control subjects were reared in white light on a 14 h on, 10 h off cycle. ERG b-wave responses to visual stimuli consisting of various wavelengths (320 to 640 nm) and irradiances were recorded. Spectral sensitivity functions were derived from irradiance versus response amplitude functions. Results: The spectral sensitivity function for the subjects reared in the BB condition showed a reduction in sensitivity to ultraviolet and short-wavelength stimuli compared to normally reared zebrafish. There was little, if any, effect on sensitivity to middle- and long-wavelength stimuli in this group. The spectral sensitivity function for the subjects reared in the GG condition showed a reduction in sensitivity to middle- and long-wavelength stimuli compared to those in the BB condition. Conclusion: As has been found in other studies, abnormal lighting environments influence zebrafish retinal development. In addition, these results illustrate that retinal development can be selectively modified by rearing subjects in different spectral environments. These results provide further support for the notion that zebrafish are a useful model for examining the effects of lighting environments on visual system development.
Keywords: 396 electroretinography: non-clinical • 537 radiation damage: light/UV • 347 chromatic mechanisms