Dopamine influences the light peak in the perfused mammalian eye.
Dopamine, cis-flupenthixol, and dibutyryl cAMP affected the standing potential and light-evoked responses of the perfused cat eye in vitro. At micromolar concentrations, dopamine, a retinal neurotransmitter, increased the standing potential of the eye. At slightly higher concentrations, dopamine abolished the "light peak," a slow voltage response to light generated by the retinal pigment epithelium. The light peak was depressed by cis-flupenthixol, a dopamine antagonist, at micromolar concentrations. Dibutyryl cAMP produced effects similar to those produced by dopamine. A possible interpretation is that the generation of the light peak involves a catecholamine-stimulated adenylate cyclase in retinal pigment epithelium that is influenced by dopamine released from retinal neurons.
D000818:Animals; D002415:Cats; D000242:Cyclic AMP / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology*; D004594:Electrophysiology; D004596:Electroretinography; D005123:Eye / Q000187:drug effects*; D005475:Flupenthixol / Q000494:pharmacology; D008027:Light; D009799:Ocular Physiological Phenomena; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000502:physiology
D000242:Cyclic AMP; D005475:Flupenthixol; D004298:Dopamine