title: Sodium and anion transport across the avian uterine (shell gland) epithelium.
abstract: The uterine (shell gland) epithelium from the domestic chicken was mounted in Ussing chambers, bathed in symmetric avian saline solution on both apical and basolateral aspects and voltage clamped at 0 mV. The epithelium exhibited a basal short circuit current (I(sc)) that was partially inhibited by the epithelial Na(+) channel (ENaC) blockers, amiloride and benzamil (IC(50) values of 0.8 and 0.12 micromol l(-1), respectively). Inhibition of basal Na(+) absorption by 10 micromol l(-1) amiloride was confirmed by measurements of transepithelial Na(+) and Cl(-) fluxes, where inhibition of the apical-to-basolateral and net Na(+) flux occurred, but no significant effects on Cl(-) fluxes were detected. The amiloride-insensitive portion of the basal I(sc) was both Cl(-) and HCO(3)(-) dependent and was inhibited by the Cl(-) channel blocker, diphenyl-2-carboxylate (DPC; 100 micromol l(-1)). Stimulation with 8-(4-chlorophenylthio)-cyclic 3'-5', adenosine monophosphate (8-cpt cAMP) produced a sustained increase in I(sc) that was dependent on both Cl(-) and HCO(3)(-). The magnitude of the amiloride-sensitive I(sc) was approximately twofold greater in birds where shell formation was complete, but oviposition had not yet occurred. In addition, the amiloride-sensitive I(sc) was greater in hens over the age of 55 weeks and in molting birds. The anion-dependent component of the basal I(sc) was reduced in older birds, and electrogenic HCO(3)(-) transport was nearly absent in molting birds. These results demonstrated that electrogenic Na(+) transport in avian shell gland was similar to the mammalian uterine epithelium and increased with age and during molting. Electrogenic Cl(-) and HCO(3)(-) transport were coupled under basal and cAMP stimulated conditions and basal anion transport decreased with age and during molting.
authors.affiliation: Cardiac Rhythm Management, Medtronic Corporation, 7000 Central Avenue NE, Minneapolis, MN 55432, USA.
authors.forename: Alisen E
authors.initials: AE
authors.lastname: Vetter
authors.forename: Scott M
authors.initials: SM
authors.lastname: O'Grady
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D000838:Anions / Q000378:metabolism*; D001639:Bicarbonates / Q000378:metabolism; D002645:Chickens / Q000378:metabolism*; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000502:physiology; D002712:Chlorides / Q000378:metabolism; D000242:Cyclic AMP / Q000494:pharmacology; D004528:Egg Shell / Q000254:growth & development*; D004848:Epithelium / Q000378:metabolism; D005260:Female; D005836:Genitalia, Female / Q000378:metabolism; D066298:In Vitro Techniques; D017136:Ion Transport / Q000187:drug effects / Q000502:physiology; D018978:Molting / Q000502:physiology; D012964:Sodium / Q000378:metabolism*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000502:physiology
chemical_list: D000838:Anions; D001639:Bicarbonates; D018118:Chloride Channels; D002712:Chlorides; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D012964:Sodium; D000242:Cyclic AMP