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Mechanism of ammonia excretion by ionocytes in medaka (Oryzias latipes) acclimated to seawater
Author(s) -
Liu SianTai
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.937.5
Subject(s) - oryzias , excretion , ammonia , chemistry , seawater , biochemistry , biology , ecology , gene
The acid‐trapping mechanism is critical for fish to excrete ammonia in fresh water. However, is it also a critical mechanism for seawater fish remains to be examined. Using a scanning ion‐selective electrode technique (SIET) to measure H + gradients, an acidic boundary layer was detected at the skin surface of SW‐acclimated medaka larvae. Adding tricine buffer or EIPA (a Na + /H + exchanger inhibitor) in seawater abolished the acid layer and decreased ammonia excretion of larvae. In situ hybridization and immunochemistry showed that slc9a2 (NHE2) and slc9a3 (NHE3) were expressed in skin ionocytes. Real‐time PCR analysis showed that slc9a3 and rhcg1 expression was induced by high ammonia acclimation. This study suggests that ionocytes play a critical role in ammonia excretion, Na + /H + exchanger ( slc9a2 and slc9a3 ) and Rh glycoprotein ( Rhcg1 ) are involved in the acid‐trapping ammonia excretion of ionocytes in seawater.