CNS distribution of two-pore-domain channels. Coronal sections were hybridized with [³³P]-labeled cRNA probes for TASK-1, TASK-3, TREK-1, TREK-2, TRAAK, and TWIK-1 and exposed to autoradiographic film. Labeling for TASK-2 in the CNS was uniformly low and therefore is not presented here. Line drawings on the far right are adapted from Paxinos and Watson (1997; reproduced with permission) and indicate the relevant labeled areas. For abbreviations, please refer to Table 2. Scale bar, 3 mm.