Fig. 5. Representative pictures of in situ hybridization of EDN1A and EDN1B mRNA in lamellar cross-sections of the seawater killifish gill. (A) The EDN1A antisense probe was localized to epithelial cells in the interlamellar region of the gill. Little staining was seen in the gill when the EDN1A sense probe was used (B). (C) The NKA antisense probe was localized to mitochondrion-rich cells. (D) EDN1B antisense probes bound to pillar cells and epithelial cells adjacent to the environment. Little staining was seen with the sense probe (E). (F) A magnification of the pillar cell EDN1B staining. Scale bars, 50 µm.