The effects of dopamine blockade on the human flash electroretinogram

Single-cell electrophysiologic studies have shown that dopamine modulates retinal activity, but its role in human retinal processing is unclear. We investigated the effects of short-term oral administration of dopaminergic receptor blocking agents on the flash electroretinogram in humans. Both chlorpromazine (25 and 50 mg) and fluphenazine (1 and 2 mg) significantly reduced electroretinogram b-wave amplitudes and also selectively reduced the amplitude of the first oscillatory potential. Implicit times were not altered. Metoclopramide (10 and 20 mg) had no effect on any electroretinographic variable. Our study indicates that dopamine receptor blocking agents with both D-1 and D-2 receptor affinities reduce the amplitude of the electroretinogram in humans.