Immunocytochemical localization of GABA and glycine in amacrine and displaced amacrine cells of macaque monkey retina.
Recent studies have varied widely in the percentages of GABA- and glycine-immunoreactive (GABA+, GLY+) amacrines reported for primate retina. We compared the distributions of GABA+ and GLY+ amacrines and displaced amacrines at seven locations along the horizontal meridian of macaque retina using postembedding immunogold labeling with silver intensification. The percentage of GABA+ amacrine profiles was higher in central retina (50-55%) than peripheral retina (30-40%), whereas the percentage of GLY+ amacrine profiles did not vary much with eccentricity (52-57%). GABA and glycine were colocalized in 5-20% of amacrines, depending on the eccentricity, whereas 5-30% of amacrines were not immunoreactive for either neurotransmitter. GABA+ amacrines were slightly larger than GLY+ amacrines or Müller cells. In the ganglion cell layer, 5-20% of neurons were labeled for either GABA or glycine and were identified as displaced amacrines. Of these, 53% were GABA+ only, 11% were GLY+ only, and 37% were double-labeled. A few large, very lightly labeled GABA+ cells were identified as ganglion cells. Other features that varied with eccentricity included the linear density of GABA+ and GLY+ amacrines, and the ratio of amacrines to Müller cells.
Koontz
M A
MA
Department of Ophthalmology, University of Washington, Seattle 98195.
Hendrickson
L E
LE
Brace
S T
ST
Hendrickson
A E
AE
D000818:Animals; D002452:Cell Count; D048429:Cell Size; D005260:Female; D005998:Glycine / Q000378:metabolism*; D007150:Immunohistochemistry; D008254:Macaca nemestrina / Q000502:physiology*; D012160:Retina / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D005680:gamma-Aminobutyric Acid; D005998:Glycine