We have examined the distribution of the glycine
transporter glyt-1 in retinae of macaques, cats, rabbits,
rats, and chickens. In all species, all glycine-containing
amacrine cells expressed immunoreactivity for glyt-1, though
the intensity of immunoreactivity for glyt-1 did not appear
to directly correlate with the intensity of immunoreactivity
for glycine in individual cells. A small subpopulation
of glycine-immunoreactive displaced amacrine cells or ganglion
cells also expressed glyt-1 in retinae from macaques, cats,
chickens, and rats but not in retinae from rabbits. In
addition, in all species examined, some displaced amacrine
cells also contained glycine but did not express glyt-1.
In monkeys, cats, and rats, populations of cells which
we interpret as being glycine-containing interplexiform
cells expressed glyt-1; these cells lacked a content of
glutamate, suggesting they are not bipolar cells. The glycine-containing
bipolar cells did not express glyt-1, suggesting that these
cells probably acquired their content of glycine by other
means such as via gap junctional connections with
glycine-containing amacrine cells.