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Urotensin II in the killifish gill: regulation of gill chloride transport
Author(s) -
Hyndman Kelly Anne,
Cornwell Emily,
Buchanan Patrick,
Evans David H
Publication year - 2010
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.24.1_supplement.813.10
Subject(s) - killifish , urotensin ii , biology , endocrinology , medicine , paracrine signalling , receptor , microbiology and biotechnology , fishery , biochemistry , fish <actinopterygii>
The endocrine, urotensin II, was first described in fishes forty years ago, and since its discovery evidence is emerging to suggest that it is a regulator of ion transport in the fish gill. The purpose of this study was to first identify if the urotensin II receptor is expressed in the euryhaline killifish gill and to elucidate its putative role in ion transport. The urotensin II receptor was partially cloned from the killifish gill, and found to be widely expressed in the tissues of the killifish. In addition, urotensin II receptor mRNA was found to significantly increase in the gill in fishes that were transferred from freshwater (FW) to sea water (SW) after 24 hrs (0.22 ± 0.05 RU vs 1.02 ± 0.4, n= 5, p= 0.05). As well, chronic acclimation of killifish to FW results in an 80% reduction of urotensin II mRNA expression (1.0 ± 0.2 RU in SW vs 0.23 ±0.04 in FW, n= 6, p = 0.014). Using the SW killifish operculum (a model for the SW teleost gill salt extrusion), urotensin II was found to significantly inhibit the short circuit current in a dose‐dependent manner. Both the nitric oxide synthase inhibitor L‐NAME and the cyclooxygenase inhibitor indomethacin reduced this inhibition, suggesting that urotensin II regulates salt transport in the SW teleost gill via intracellular production of both NO and prostaglandins. In addition, we immunolocalized the urotensin II receptor to the mitochondrion‐rich cell of the gill. Take together, we conclude that urotensin II is a regulator of transport in the gill, and the urotensin II receptor is regulated by environmental salinity with very low levels in FW acclimated fish. Funding the National Science Foundation IOB‐0519579 to DHE.