Distribution of catecholaminergic cells in the retina of the rat, guinea pig, cat, and rabbit: Independence from ganglion cell distribution

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Abstract
By using an antibody against tyrosine hydroxylase (TH), the rate‐limiting enzyme in the production of catecholamines, we have examined the morphology and distribution of catecholaminergic cells in the retinas of the rat, guinea pig, cat, and rabbit. In the albino rat, as reported by others, most TH‐immunoreactive (TH‐IR) cells were amacrine cells, and formed two morphological classes. Cells of one class (class 1) are stellate amacrine cells, the somata of most being in the inner part of the inner nuclear layer (INL). Cells of the second class (class 2) were seen only as small somata, also in the inner part of the INL. Cells of both classes were found in all areas of the retina, with a distinct but broad concentration around the superior‐temporal margin of the retina. A small number of TH‐IR interplexiform cells was seen. In the pigmented rat, only class 1 cells were recognized, also concentrating at the superior‐temporal margin. In the guinea pig, cat, and rabbit, TH‐IR cells also seemed to form one morphological class of amacrine cells, which resembled the class 1 cells of the albino rat. In the guinea pig and cat, their distribution resembled that seen in the rat, with the cells concentrating at the superior‐temporal margin of the retina. In the rabbit, TH‐IR cells concentrated weakly in the visual streak, but at both ends of the streak the concentration of TH‐IR cells extended farther peripherally than the concentration of ganglion cells. Overall, the distribution of TH‐IR cells seems largely or (in the rabbit) partially independent of the distribution of ganglion cells. This independence raises questions of the development and function of this group of amacrine cells.