title: Adenosine stimulates Cl- channels of nonpigmented ciliary epithelial cells.
abstract: Ciliary epithelial cells possess multiple purinergic receptors, and occupancy of A1 and A2 adenosine receptors is associated with opposing effects on intraocular pressure. Aqueous adenosine produced increases in short-circuit current across rabbit ciliary epithelium, blocked by removing Cl- and enhanced by aqueous Ba2+. Adenosine's actions were further studied with nonpigmented ciliary epithelial (NPE) cells from continuous human HCE and ODM lines and freshly dissected bovine cells. With gramicidin present, adenosine (> or = 3 microM) triggered isosmotic shrinkage of the human NPE cells, which was inhibited by the Cl- channel blockers 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB) and niflumic acid. At 10 microM, the nonmetabolizable analog 2-chloroadenosine and AMP also produced shrinkage, but not inosine, UTP, or ATP. 2-Chloroadenosine (> or = 1 microM) triggered increases of whole cell currents in HCE cells, which were partially reversible, Cl- dependent, and reversibly inhibited by NPPB. Adenosine (> or = 10 microM) also stimulated whole cell currents in bovine NPE cells. We conclude that occupancy of adenosine receptors stimulates Cl- secretion in mammalian NPE cells.
authors.affiliation: Department of Physiology, The University of Pennsylvania, Philadelphia 19104-6085, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Carré
authors.forename: C H
authors.initials: CH
authors.lastname: Mitchell
authors.forename: K
authors.initials: K
authors.lastname: Peterson-Yantorno
authors.forename: M
authors.initials: M
authors.lastname: Coca-Prados
authors.forename: M M
authors.initials: MM
authors.lastname: Civan
mesh_terms: D015762:2-Chloroadenosine / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology*; D000249:Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D001464:Barium / Q000494:pharmacology; D002417:Cattle; D002460:Cell Line; D002478:Cells, Cultured; D018118:Chloride Channels / Q000187:drug effects / Q000502:physiology*; D002924:Ciliary Body / Q000502:physiology*; D006096:Gramicidin / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009544:Niflumic Acid / Q000494:pharmacology; D009579:Nitrobenzoates / Q000494:pharmacology; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000502:physiology*; D011817:Rabbits; D018047:Receptors, Purinergic P1 / Q000187:drug effects / Q000502:physiology; D013997:Time Factors
chemical_list: D018118:Chloride Channels; D009579:Nitrobenzoates; D018047:Receptors, Purinergic P1; D006096:Gramicidin; D015762:2-Chloroadenosine; D001464:Barium; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D000249:Adenosine Monophosphate; D009544:Niflumic Acid; D000241:Adenosine