title: Forskolin stimulation of water and cation permeability in aquaporin 1 water channels.
abstract: Aquaporin 1, a six-transmembrane domain protein, is a water channel present in many fluid-secreting and -absorbing cells. In Xenopus oocytes injected with aquaporin 1 complementary RNA, the application of forskolin or cyclic 8-bromo- adenosine 3',5'-monophosphate increased membrane permeability to water and triggered a cationic conductance. The cationic conductance was also induced by direct injection of protein kinase A (PKA) catalytic subunit, reduced by the kinase inhibitor H7, and blocked by HgCl2, an inhibitor of aquaporin 1. The cationic permeability of the aquaporin 1 channel is activated by a cyclic adenosine monophosphate-dependent mechanism that may involve direct or indirect phosphorylation by PKA.
authors.affiliation: Department of Physiology, University of Arizona, Tucson, AZ 85724-5051, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Yool
authors.forename: W D
authors.initials: WD
authors.lastname: Stamer
authors.forename: J W
authors.initials: JW
authors.lastname: Regan
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D051398:Aquaporin 1; D020346:Aquaporins; D002412:Cations / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects*; D005576:Colforsin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007473:Ion Channels / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D007546:Isoquinolines / Q000494:pharmacology; D008627:Mercuric Chloride / Q000494:pharmacology; D009865:Oocytes; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D010879:Piperazines / Q000494:pharmacology; D018075:RNA, Complementary / Q000235:genetics; D014867:Water / Q000378:metabolism*; D014981:Xenopus
chemical_list: D020346:Aquaporins; D002412:Cations; D004791:Enzyme Inhibitors; D007473:Ion Channels; D007546:Isoquinolines; D010879:Piperazines; D018075:RNA, Complementary; D014867:Water; D051398:Aquaporin 1; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D008627:Mercuric Chloride; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases