REDUCTION OF RED-GREEN DISCRIMINATION BY DOPAMINE D1 RECEPTOR ANTAGONISTS AND RETINAL DOPAMINE DEPLETION

Reduction of wavelength discrimination ability in the 560-640 nm range , but not in the 404-540 nm range, has been demonstrated in goldfish a fter intravitreal injection of D1-dopamine receptor antagonists. Intra vitreal injection of the dopaminergic neurotoxin 6-OH-dopamine severel y reduced wavelength discrimination ability in the 540-661 nm range wi thin 3 days. Discrimination ability could be reconstituted by the D1-a gonist SKF 38393. Animals recovered from injection of 6-OH-dopamine wi thin 14-16 days. No change of wavelength discrimination was induced by 6-OH-dopamine in the 461-540 nm range. We conclude that under photopi c conditions dopamine modulates retinal mechanisms involved in red-gre en colour coding via D1-dopamine receptor-like binding sites. Copyrigh t (C) 1996 Elsevier Science Ltd.