Figure 1. Embryonic raphe neurones stain for the erg1 channel protein and serotonin.

A, the rhombencephalon after dissection from a rat embryo. Inset, dorsal view of a rat embryo (E15) with the asterisk (*) indicating the position of the rhombencephalon. B–D, area of the rhombencephalon as indicated by the black square in A after labelling with antibodies against erg1 (B) and serotonin (C). D, overlay of B and C. Serotonin and erg1 positive cells are located along the median line forming the raphe nucleus. This region was further dissected and dissociated for cell culture. Scale bars in A, 1 mm; B–D, 0.5 mm.