Effects of intraocular injections of 6-hydroxydopamine on dopamine-dependent cyclic AMP accumulation in intact pieces of carp retina.

Dopamine-stimulated cyclic AMP accumulation was measured in intact pieces of carp retina following intraocular injections of the dopaminergic neurotoxin 6-hydroxydopamine (6-OHDA). This treatment is known to induce a selective destruction of dopaminergic nerve terminals, and in these experiments caused a 94% reduction in retinal dopamine content. However, dopamine-dependent cyclic AMP accumulation was essentially unaltered in retinas exposed to 6-OHDA, indicating that the dopamine receptors linked to adenylate cyclase in the carp retina are located mainly on postsynaptic elements, and not presynaptically on the dopaminergic terminals.