Two-pore-domain channel expression in dorsal root ganglia. As shown by dark-field microscopy, all seven transcripts were expressed in dorsal root ganglia, and especially high densities of silver grains were seen for TASK-1 (A), TASK-2 (B), and TRAAK (G). TASK-3 (C) was expressed at high levels but by a much more limited proportion of the cells. Labeling for TWIK-1 was for the most part restricted to larger neurons; it is shown at low power inD, with a higher-power view of the indicated neuron (arrows) shown in H. Scale bar:A–G, 400 μm; H, 50 μm.