title: Elevated dopamine concentration in light-adapted zebrafish retinas is correlated with increased dopamine synthesis and metabolism.
abstract: Probing zebrafish (Danio rerio) retinal cryostat sections, collected either 8 h into the light or dark cycle, with an antibody against tyrosine hydroxylase (TH) identified a single population of immunopositive cells in the inner retina. However, the observed labeling patterns were not identical in both sets of tissues - label intensity was brighter in light-adapted tissue. This difference was quantified by probing western blots of retinal homogenates with the same TH antibody, which showed that TH expression increased by 42% in light-adapted tissue. High-performance liquid chromatography with electrochemical detection revealed that the concentrations of both dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) are also elevated in light-adapted zebrafish retinal tissue. Dopamine levels increased by 14% and DOPAC levels increased by 25% when measured in retinal homogenates harvested during the light cycle. These results indicate that dopamine levels in zebrafish retina are significantly increased in light-adapted tissue. The increase in dopamine content is correlated with an increase in both TH and DOPAC, suggesting that changes in dopamine concentration are due to light-adaptive changes in the synthesis, release and metabolism of dopamine. Dopamine concentration is elevated in lighted-adapted zebrafish retinas. This increase is correlated with an increase in both tyrosine hydroxylase (TH) and DOPAC (3,4-dihydroxyphenylacetic acid), suggesting that changes in dopamine concentration are due to light-adaptive changes in the synthesis, release and metabolism of dopamine. This is applicable to studies examining retinal mutants, the role of dopamine in disease or visual system development.
authors.affiliation: Department of Biology, American University, Washington, District of Columbia, USA.
authors.forename: Victoria P
authors.initials: VP
authors.lastname: Connaughton
authors.affiliation: Department of Psychology, American University, Washington, District of Columbia, USA.
authors.forename: Bradley
authors.initials: B
authors.lastname: Wetzell
authors.affiliation: Department of Biology, American University, Washington, District of Columbia, USA.
authors.forename: Lynne S
authors.initials: LS
authors.lastname: Arneson
authors.affiliation: Department of Biology, American University, Washington, District of Columbia, USA.
authors.forename: Vittoria
authors.initials: V
authors.lastname: DeLucia
authors.affiliation: Department of Psychology, American University, Washington, District of Columbia, USA.
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Riley
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000222:Adaptation, Physiological; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D008027:Light; D017440:Photoperiod; D012160:Retina / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D015027:Zebrafish
chemical_list: D015102:3,4-Dihydroxyphenylacetic Acid; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine
keywords: HPLC; adaptational state; dopamine; interplexiform cells; retina; tyrosine hydroxylase