Immunolocalization of Na+-K+ ATPase in Response to Different Salinity Levels in Gills of Cyprinus carpio

Adaptation to changes in environmental salinities have been widely studied in different euryhaline fish species but there has been less interest in studies on freshwater stenohaline fish adaptation to saline environments. Common carp, Cyprinus carpio is a suitable species to assess the effects of changes in salinities on stenohaline fish. 90 individuals of Common carp (986±0.36 g) were distributed in 6 experimental groups exposed to different salinities of 3, 6, 9, 12 and 15 g/l and a control group. At the end of the experimental period gill tissue from each experimental group was sampled and fixed in 4% paraformaldehyde. Immunolocalization of Na+-K+ ATPase was assayed by monoclonal antibody against α5 subunit of this protein (Hybridoma, USA) in 5 µm sections. Based on the results obtained mitochondria rich cells (MRCs) were present in the epithelium of both lamella and filament but after adaptation to increased salinities these type of epithelial cells (MRCs) were observed only in the epithelium of gill filament and their densities increased as an response to increasing in environmental salinities (P<0.05).