TASK-2 is expressed in proximal neurons in the rat retina

TASK-2 is a member of tandem-pore domain potassium channels that regulate neuronal excitability. In this study we investigated the expression of TASK-2 in neuronal elements in the inner retina of rat by immunofluorescence double labeling. In contrast to weak expression in the outer retina, TASK-2 is strongly expressed in the inner retina. TASK-2 immunoreactivity was diffusely distributed throughout the inner plexiform layer. Double-labeling experiments revealed that TASK-2 was expressed in gamma-aminobutyric acid amacrine cells (GABAergic amacrine cells), including both dopaminergic and cholinergic ones. The immunostaining appeared on the membrane, cytoplasm, and somatodendritic compartments of these cells. In AII glycinergic amacrine cells, however, only faint punctuate staining, if any, was seen. In addition, ganglion cells were also intensely labeled by TASK-2.