Benzodiazepines suppress the light response of retinal dopaminergic neurons in vivo.

Sedative dosages of the benzodiazepine, diazepam (76 micro mol/kg, i.p.), reduce the light-evoked increase in retinal dopamine turnover, while intraocular applications of the water-soluble benzodiazepine, flurazepam (0.50 or 1.0 micro mol/eyeball), produce a dose-dependent suppression of light-enhanced dopamine synthesis. These results provide the first evidence that the benzodiazepines alter a physiologically important retinal response in vivo. They also suggest that some the visual effects produced by the benzodiazepines may have an intraretinal locus of action.