Changes in retinal dopaminergic cells and dopamine rhythmic metabolism during the development of a glaucoma-like disorder in quails.

Purpose. To examine the possible correlation between a dysfunction of the daily rhythm of retinal dopamine (DA) and the development of a glaucoma-like disorder in an animal model, the al mutant quail (Coturnix roturnix japonica). Methods. The morphology and density of DA-containing cells labeled immunohistochemically with an anti-tyrosine hydroxylase (TH) antibody were correlated with the diurnal and nocturnal contents of DA and 3,4-dihydroxyphenylacetic acid (DOPAC) determined by high-pressure liquid chromatography with electrochemical detection. Results. The number of TH-immunoreactive cells was lower than normal in mutant quails suffering from the disorder. There were considerably fewer cells in the central retina, and the DA metabolism was reduced in parallel. The nocturnal DA content was lower than the diurnal level in normal quails, but there was no such circadian fluctuation in mutant quails. Conclusions. This glaucoma-like disorder in quails is correlated with the degeneration of DA-containing amacrine cells and a dysfunction of the circadian rhythmicity of DA synthesis.