A SUBGROUP OF BIPOLAR CELLS IN HUMAN RETINA IS GABA-IMMUNOREACTIVE

The distribution of GABA in the perifoveal and the near and far peripheral region of human retina was studied with peroxidase anti-peroxidase immunocytochemistry applied on semithin epoxy resin sections. Among the labeled amacrine cells in these regions, four types can be identified: putative diffuse A2 amacrines, stratified semilunar amacrines, interstitial amacrines and small displaced amacrines. GABA-immunoreactive inter-plexiform cells and ganglion cells also occur. Contrary to previous post-embedding studies, our preparations show that some bipolar cells in the near and far peripheral region are GABA-immunopositive. This indicates that a number of bipolar cells in human retina does have an enhanced GABA content.