Neurotransmitter properties of the newborn human retina.

Human retinal tissue from a newborn was examined autoradiographically for the presence of highaffinity uptake and localization of the following putative neurotransmitters: dopamine, glycine, GAB A, aspartate, and glutamate. In addition, the dopamine content of this newborn retina was measured by high pressure liquid chromatography. Our study reveals that specific uptake mechanisms for 3Hglycine, 3H-dopamine, and 3H-GABA are present at birth. However, the number and distribution of cells labeled with each of these 3H-transmitters are not identical to those observed in adult human retinas. Furthermore, the amount of endogenous dopamine in the newborn retina is approximately V20 the adult level. Photoreceptor-specific uptake of 3H-glutamate and 3H-aspartate are not observed. These findings indicate that, while some neurotransmitter-specific properties are present at birth, significant maturation of neurotransmitter systems occurs postnatally.