TREK-2; TREK-2 immunoreactivity was detected predominantly within Mϋller cells (Fig. 4G,H and J,K). However, low levels of TREK-2 immunoreactivity were also observed for a number of cells located in the GCL (Fig. 4H and K) and also the INL (typically only 3–5 cells per retina section) (Fig. 4J), including 30.3% (30 of 99 cells counted) of Brn3a positive RGCs (Fig. 4L). TRAAK; The pattern of TRAAK immunoreactivity observed in the adult mouse retina was highly similar to that observed for TREK-2 (Fig. 5). TRAAK immunoreactivity was detected at high levels within Mϋller cells (Fig. 5A,B), with lower levels of staining observed for a subset of cells located in the GCL (Fig. 5B) and INL (Fig. 5C). Low levels of TRAAK immunoreactivity were detected for 15.5% (14 of 90 cells counted) of Brn3a positive RGCs. (Fig. 5D–F). Consistent with our qPCR data, TRAAK immunoreactivity was not observed in the retina prior to P14.