Effects of dark-rearing on the retinal dopaminergic system in the neonatal and postnatal guinea pig.

To appraise the extent of light responsivity of the retinal dopaminergic system in the early postnatal period, dopamine content (DA) of retinas of cycling-light-reared and dark-reared guinea pigs was determined. DA storage postnatally was suppressed in dark-reared animals. Their retinas responded to a brief light stimulus by rapidly increasing DOPA synthesis and DA utilization, but not to the extent of the response of cycling-light-reared animals. Dopaminergic retinal neurones depend on light stimulus for the complete development of some of their neurochemical characteristics.