title: Role of prostaglandin E2 in regulation of low and high water osmotic permeability in frog urinary bladder.
abstract: The water osmotic permeability of frog urinary bladder was found to be increased from 0.08 +/- 0.01 to 1.28 +/- 0.20 microl/min cm2 when serosal bathing medium was changed 4 times for a fresh Ringer solution. High epithelium permeability is accompanied by an increased content of cyclic AMP in the bladder tissue (by 42%, P < 0.01), higher activity of both basal and forskolin-stimulated membrane adenylate cyclase (AC) (by 109% and 74%, respectively, P < 0.05) and by appearance of aggregates of intramembranous particles in the apical membrane. The water flow was inhibited by 10(-9)-10(-5) M prostaglandin E2 (PGE2); the inhibitory effect was eliminated in the presence of 10(-4) M N-ethylmaleimide. The increase of water permeability due to changes of the bathing medium was accompanied by a decrease of serosal PGE2 concentration from 14.8 +/- 1.0 in the 1st solution to 0.6 +/- 0.1 nM in the 5th. 10(-6) M PGE2 in vitro inhibited the activity of membrane AC from highly permeable bladders by 33.4% (P < 0.02). Pretreatment of the membranes with 10 microg/ml pertussis toxin (PT) completely reversed this effect (+149%, P < 0.01). A significant activation of AC was also observed under 10(-10) M PGE2 (by 196%). These data demonstrate that the water permeability could be markedly increased independently of ADH, suggesting that the trigger role in activation of water transport is played by a decreased level of PGE2 which could stimulate AC.
authors.affiliation: Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia.
authors.forename: R G
authors.initials: RG
authors.lastname: Parnova
authors.forename: E I
authors.initials: EI
authors.lastname: Schakhmatova
authors.forename: S A
authors.initials: SA
authors.lastname: Plesneva
authors.forename: E V
authors.initials: EV
authors.lastname: Getmanova
authors.forename: E V
authors.initials: EV
authors.lastname: Korolev
authors.forename: Y Y
authors.initials: YY
authors.lastname: Komissarchik
authors.forename: Y V
authors.initials: YV
authors.lastname: Natochin
mesh_terms: D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D015232:Dinoprostone / Q000037:antagonists & inhibitors / Q000502:physiology*; D004848:Epithelium / Q000378:metabolism; D005033:Ethylmaleimide / Q000494:pharmacology; D066298:In Vitro Techniques; D009995:Osmosis / Q000187:drug effects; D037342:Pertussis Toxin; D011896:Rana temporaria; D001743:Urinary Bladder / Q000378:metabolism* / Q000648:ultrastructure; D014668:Vasotocin / Q000494:pharmacology; D010566:Virulence Factors, Bordetella
chemical_list: D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D010566:Virulence Factors, Bordetella; D000242:Cyclic AMP; D037342:Pertussis Toxin; D015232:Dinoprostone; D005033:Ethylmaleimide; D014668:Vasotocin