Depletion of retinal dopamine increases brightness perception in goldfish.

摘要: The effect of unilateral depletion retinal dopamine on goldfish visual behavior was studied using a behavioral reflex, the dorsal light reaction (DLR). Retinal depleted by intraocular injections 6-hydroxydopamine (6-OHDA) two successive days. By 2 weeks postinjection, interplexiform cells (DA-IPC) were not detected tyrosine-hydroxylase immunoreactivity (TH-IR). 6 generation DA-IPC observed at marginal zone and 9 months 2-3 rows present zone. Neurites extended several hundred micrometers toward central retina. all 6-OHDA lesioned fish tilted 7-15 deg injected eye under uniform overhead illumination. tilting did occur scotopic illumination reappeared within 1 min adaptation. Quantitation DLR showed that behaved as if 2.4 log units more intense to eye. Partial recovery paralleling reappearance Tilting also induced injection with D1 D2 receptor antagonists, SCH 23390 S(-)-sulpiride, respectively. Fish tilt they adapted time injection. animals dark-adapted for 3 h left in dark postinjection. drug-injected adaptation gradually returned vertical h. response S(-)-sulpiride stronger (approximately 20 vs. approximately 5 deg) occurred lower concentration (1 microM 10 microM) compared 23390. We conclude mimics increasing luminosity output is directly involved photopic function.