Fig. 3. Immunohistochemical localization of Na⁺/K⁺-ATPase in primary cultured eel gas gland cells. The confocal image shows three optical sections of a gas gland cell in the xy (A), the yz (B) and the xz (C) planes. The white bars in A (the xy section) indicate the locations of the other two sections; the white bar in C (the xz section) indicates the location of the xy section in A. Note that Na⁺/K⁺-ATPase immunoreactivity is located at lateral cell membranes, but there is no immunoreactivity at the apical membranes. Scale bar, 1 µm.