Voltage-gated K+ channel subunits on cholinergic and dopaminergic amacrine cells

The expression of voltage-gated K+ (Kv) channel subunits on rat retinal cholinergic and dopaminergic amacrine cells was studied using double immunofluorescence labeling and confocal laser scanning microscopy. Staining for IKv3.Ib was found in the cholinergic cells, being present on the membrane of somata, and on the processes, but not in the dopaminergic cells. Kv4.3-immunoreactivity was localized on the somatodendritic compartment of the dopaminergic cells, but was not found in the cholinergic cells. Differential expression between the two cell types was not found for 10 other subunits tested. These results suggest that the Kv3.lb and Kv4.3 subunits may differentially contribute to the electrophysiological properties underlying distinct functions of these two retinal interneurons.