title: Pendrin immunoreactivity in the gill epithelium of a euryhaline elasmobranch.
abstract: Pendrin is an anion exchanger in the cortical collecting duct of the mammalian nephron that appears to mediate apical Cl(-)/HCO3(-) exchange in bicarbonate-secreting intercalated cells. The goals of this study were to determine 1) if pendrin immunoreactivity was present in the gills of a euryhaline elasmobranch (Atlantic stingray, Dasyatis sabina), and 2) if branchial pendrin immunoreactivity was influenced by environmental salinity. Immunoblots detected pendrin immunoreactivity in Atlantic stingray gills; pendrin immunoreactivity was greatest in freshwater stingrays compared with freshwater stingrays acclimated to seawater (seawater acclimated) and marine stingrays. Using immunohistochemistry, pendrin-positive cells were detected on both gill lamellae and interlamellar regions of freshwater stingrays but were more restricted to interlamellar regions in seawater-acclimated and marine stingray gills. Pendrin immunolabeling in freshwater stingray gills was more apical, discrete, and intense compared with seawater-acclimated and marine stingrays. Regardless of salinity, pendrin immunoreactivity occurred on the apical region of cells rich with basolateral vacuolar-proton-ATPase, and not in Na(+)-K(+)-ATPase-rich cells. We suggest that a pendrin-like transporter may contribute to apical Cl(-)/HCO3(-) exchange in gills of Atlantic stingrays from both freshwater and marine environments.
authors.affiliation: Department of Zoology, University of Florida, Gainesville, Florida 32611, USA. pmpierma@zoo.ufl.edu
authors.forename: Peter M
authors.initials: PM
authors.lastname: Piermarini
authors.forename: Jill W
authors.initials: JW
authors.lastname: Verlander
authors.forename: Ines E
authors.initials: IE
authors.lastname: Royaux
authors.forename: David H
authors.initials: DH
authors.lastname: Evans
mesh_terms: D000818:Animals; D001934:Branchial Region / Q000378:metabolism; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018940:Elasmobranchii / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D005880:Gills / Q000166:cytology / Q000378:metabolism*; D015151:Immunoblotting; D007150:Immunohistochemistry; D026901:Membrane Transport Proteins; D012623:Seawater; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D000076988:Sulfate Transporters; D014018:Tissue Distribution; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D026901:Membrane Transport Proteins; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters; D025262:Vacuolar Proton-Translocating ATPases; D000254:Sodium-Potassium-Exchanging ATPase