Immunolocalisation of aquaporin 3 in the gill and the gastrointestinal tract of the European eel Anguilla anguilla (L.)

• Main Authors: Lignot, J-H, Cutler, Christopher Paul, Hazon, Neil, Cramb, Gordon
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2002
• Subjects: aquaporin 3; teleost fish; water channel; urea; European eel; Anguilla anguilla; gill; intestine; immuno-histochemistry; immuno-gold; ATRIAL-NATRIURETIC-PEPTIDE; CHLORIDE CELL; SEAWATER EEL; INTESTINAL-MUCOSA; GLANDULAR TISSUES; COMPLEX TISSUES; RAINBOW-TROUT; FISH GILLS; TRANSPORT
• Online Access: https://risweb.st-andrews.ac.uk/portal/en/researchoutput/immunolocalisation-of-aquaporin-3-in-the-gill-and-the-gastrointestinal-tract-of-the-european-eel-anguilla-anguilla-l(44e3acaa-be47-4374-b73c-e9f0d217612d).html; http://www.scopus.com/inward/record.url?scp=0036736473&partnerID=8YFLogxK

The expression of a putative water channel protein, aquaporin 3 (AQP-3), has been localised within branchial and intestinal tissues from the 'silver' life stage of the European eel Anguilla anguilla, using a specific polyclonal antibody directed against the C-terminal of the amino acid sequence. Western blots using the AQP-3 antiserum identified the presence of a major immunoreactive protein of 24 kDa in extracts of gills from both freshwater (FW) and 3 week seawater (SW)-acclimated eels. SW acclimation induced a 65% reduction in AQP-3 protein abundance in the gill extracts. AQP-3 immunoreactivity was apparent throughout the branchial epithelium from both FW and SW-acclimated fish, but especially so within the chloride cells, which also stained heavily with specific antisera for the beta-subunit of the Na, K-ATPase. AQP-3 immunoreactivity not only colocalised with Na, K-ATPase within the basolateral tubular network but also stained the apical regions of the chloride cell where Na, K-ATPase was absent. Although there were no obvious differences in expression between the chloride cells of FW and SW-acclimated fish, considerably higher intensities of immunoreactivity were apparent near the periphery of the non-chloride cells of FW fish, especially within cells forming the base of the primary filaments and the branchial arch. AQP-3 inummoreactivity was also detected in intra-epithelial macrophage-like cells within the intestine of FW and SW-acclimated eels and in the mucous cells of the rectal epithelium of SW-acclimated fish. These results suggest that AQP-3 may play an important functional role in osmoregulation the teleostean gill but is unlikely to be responsible for the increases in intestinal water absorption that occur following SW acclimation.