Midget and parasol ganglion cells of the primate retina express the alpha 1 subunit of the glycine receptor

Glycine is a major inhibitory neurotransmitter in the mammalian retina and has been shown to influence the responses of ganglion cells. Midget and par asol ganglion cells serve distinct physiological roles in the primate retin a and show differences in their response characteristics to light stimuli. In the present study, we addressed the question of whether the expression o f glycine receptors differs in midget and parasol ganglion cells. Ganglion cells in the retinae of marmoset and macaque monkeys were injected with Neu robiotin in a live in vitro retinal whole-mount preparation. Retinal pieces were then processed with an antibody against the alpha 1 subunit of the gl ycine receptor. Strong punctate immunoreactivity indicative of synaptic loc alization is present in the ON and OFF sublamina of the inner plexiform lay er. Many of the immunoreactive puncta coincide with the dendrites of both m idget and parasol ganglion cells. Immunoreactive puncta are present on dist al and proximal dendrites of ON and OFF cells. These results suggest that O N and OFF midget and parasol cells do not differ with respect to the distri bution of the alpha 1 subunit of the glycine receptor.