[Effect of UVA on biosynthesis of melatonin in the retina]

No difference in the retinal acetylserotonin-methyltransferase was found in two groups of quail which were exposed to irradiation of 0.1 W/m2 with green and blue light respectively for 1 hour. Decreased retinal enzyme activities (isoelectric point pH 5.0) were observed in response to exposure to green and UVA light concomitantly with increased irradiation. Retinal enzyme activity in response to blue light was lower than in response to UVA light (0.1 W/m2). Although exposure to UVA light affects the visual process only slightly, melatonin biosynthesis was shown to be influenced significantly. Since melatonin is said to play an important role in light adaptation processes, it may be suggested that an imbalance between visual process and light adaptation may occur, predominantly in the aphakic eye.