Exposure to Light Accelerates the Formation of Dopamine from Exogenous L-DOPA in the Rat Retina

Dopaminergic neurons of retina are activated when rats are placed in a lighted environment. L-DOPA, the precursor of dopamine, was administered to rats that were housed either in the light or the dark. In the light more dopamine and its metabolite 3,4-dihydroxyphenylacetic acid were formed from L-DOPA when compared with animals given the same dose of L-DOPA, but kept in the dark. Our results suggest that the in vivo decarboxylation of DOPA may be modulated by neuronal activity in the rat retina.