Circadian rhythms of behavioral cone sensitivity and long wavelength opsin mRNA expression: a correlation study in zebratish

P Li, S Temple, Y Gao, TJ Haimberger, CW Hawryshyn, L Li*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

36 Citations (Scopus)

Abstract

Using a behavioral assay based on visually mediated escape responses, we measured long-wavelength-sensitive red cone (LC) sensitivities in zebrafish. In a 24 h period, the zebrafish were least sensitive to red light in the early morning and most sensitive in the late afternoon. To investigate if the fluctuation of behavioral cone sensitivity correlates with opsin gene expression, we measured LC opsin mRNA expression at different times in the day and night under different lighting conditions. Under a normal light-dark cycle, the expression of LC opsin mRNA determined by real-time RT-PCR was low in the early morning and high in the late afternoon, similar to the fluctuation of behavioral cone sensitivity. This rhythm of LC opsin mRNA expression, however, dampened out gradually in constant conditions. After 24 h of constant light (LL), the expression of LC opsin mRNA dropped to levels similar to those determined in the early morning in control animals. By contrast, when the zebrafish were Kept in constant dark (DD), the expression of LC opsin mRNA increased, to levels about 30-fold higher than the expression in the early morning in control animals. This day-night fluctuation in LC opsin mRNA expression was correlated to changes in opsin density in the outer segment of cone photoreceptor cells. Microspectrophotometry (MSP) measurements found significant differences in red cone outer segment optical density with a rhythm following the behavioral sensitivity. Furthermore, dopamine modulated the circadian rhythms in expression of LC opsin mRNA. Administration of dopamine increased LC opsin mRNA expression, but only in the early morning.

Original languageEnglish
Pages (from-to)497-504
Number of pages8
JournalJournal of Experimental Biology
Volume208
Issue number3
DOIs
Publication statusPublished - Feb 2005

Keywords

  • circadian rhythm
  • opsin mRNA expression
  • behavioral visual sensitivity
  • zebrafish
  • RETINAL BIPOLAR CELLS
  • CGMP-GATED CHANNELS
  • VISUAL SENSITIVITY
  • PHOTORECEPTOR CELL
  • DOPAMINERGIC REGULATION
  • ZEBRAFISH MUTANTS
  • VERTEBRATE CLOCK
  • GOLDFISH RETINA
  • OUTER SEGMENTS
  • GANGLION-CELLS

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