Fig. 7. Localisation of epithelial calcium channel (ECaC) and Na⁺/K⁺-ATPase mRNA and protein in rainbow trout (Oncorhynchus mykiss) gill epithelia. (A) A representative image of a gill section probed with a homologous ECaC oligonucleotide probe: arrows labelled a indicate cells expressing detectable levels of ECaC mRNA; arrows labelled b indicate MRCs expressing detectable levels of ECaC mRNA and those labelled c indicate MRCs that do not appear to express high levels of ECaC mRNA. (B) A representative image of a gill section treated with primary antibodies against ECaC and Na⁺/K⁺-ATPase; the cell nuclei appear blue, ECaC appears green and Na⁺/K⁺-ATPase appears red; co-localization of ECaC with Na⁺/K⁺-ATPase appears yellow; asterisks indicate areas of intense ECaC mRNA or protein at the tips of lamellae where MRCs are rarely found. (C) A representative image of a gill section probed with a homologous Na⁺/K⁺-ATPase oligonucleotide probe.