Fig. 3. Immunohistochemical demonstration of Na⁺/K⁺-ATPase immunoreactive cells (chloride cells) in gills of (A) 15°C-acclimated and (B) 29°C-acclimated carp. Chloride cells are more abundant and larger in the gills of 15°C-acclimated carp. Representative examples are shown at the same magnification. Scale bars, 100 µm.