Cholinergic amacrine cells in the rabbit retina accumulate muscimol

The cholinergic amacrine cells of the rabbit retina form two mosaics placed symmetrically on either side of the inner plexiform layer. Recently, these cells have been reported to contain immunocytochemical markers for GABA. In this paper, we labeled the cholinergic cells with DAPI, then incubated the retina in [3H]-muscimol, a neuronal marker for GABA. Subsequently, we converted the DAPI fluorescence of the displaced cholinergic matrix to an opaque product by photooxidation in the presence of DAB. Autoradiography showed that all of the displaced cholinergic amacrine cells were labeled with [3H]-muscimol, thus confirming the immunocytochemical results. The cholinergic cells account for approximately 80% of the cells in the ganglion cell layer which take up [3H]-muscimol.