Distribution of the glycine transporter glyt-1 in mammalian and nonmammalian retinae

We have examined the distribution of the glycine transporter glyt-1 in reti nae of macaques, cats, rabbits, rats, and chickens. In all species, all gly cine-containing amacrine cells expressed immunoreactivity for glyt-1, thoug h the intensity of immunoreactivity for glyt-1 did not appear to directly c orrelate with the intensity of immunoreactivity for glycine in individual c ells. A small subpopulation of glycine-immunoreactive displaced amacrine ce lls 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 sp ecies examined, some displaced amacrine cells also contained glycine but di d not express glyt-1. In monkeys, cats, and rats, populations of cells whic h we interpret as being glycine-containing interplexiform cells expressed g lyt-1; these cells lacked a content of glutamate, suggesting they are not b ipolar cells. The glycine-containing bipolar cells did not express glyt-1, suggesting that these cells probably acquired their content of glycine by o ther means such as via gap junctional connections with glycine-containing a macrine cells.