Fig. 5. Immunocytochemical localization of Na++K+-ATPase 
-subunit protein in the basolateral membrane of gill epithelial cells in the blue crab Callinectes sapidus. (A) Phase-contrast photomicrograph of portions of two cross-sectioned gill lamellae. c, cuticle; e, epithelial layer; s, intralamellar septum; h, hemolymph space. (B) Immunocytochemical identification of -subunit protein using the 5 monoclonal antibody against a highly conserved cytosolic epitope. Intense fluorescence is evident in the basolateral membrane region (b) but not the apical membrane region (a) of the epithelial cells. Scale bars, 100 µm.
