title: Beta-adrenergic regulation of gap-junctional intercellular communication in cultured rabbit gastric epithelial cells.
abstract: The effect of a beta-adrenergic agonist, isoproterenol, on gap-junctional intercellular communication (GJIC) and intracellular cyclic AMP (cAMP) content was investigated in cultured rabbit gastric epithelial cells. Isoproterenol rapidly enhanced GJIC determined by the Lucifer yellow transfer at 10(-6) and 10(-5) M but the effect at 10(-6) M was variable. The enhancement of GJIC by 10(-5) M isoproterenol, which disappeared within 10 or 30 min, was inhibited by a beta blocker, propranolol. Isoproterenol (10(-6) M) greatly increased cAMP at 5 min and much more so at 20 min after its addition. Colforsin (also known as forskolin) and 3-isobutyl-1-methylxanthine (IBMX) enhanced GJIC until 16 and 20 min after their addition, respectively. Both colforsin and IBMX increased the cAMP content by a lesser extent than 10(-6) M isoproterenol. Isoproterenol (10(-5) M) inhibited the GJIC enhanced by colforsin or IBMX. Propranolol abolished the inhibition of GJIC by isoproterenol in the presence of IBMX. Both amiloride, an inhibitor of the Na+/H+ exchanger, and nigericin, a K+/H+ antiporter, inhibited the GJIC enhanced by isoproterenol, IBMX, colforsin and irsogladine. An inhibitor of cAMP-dependent protein kinase A, H-89 (N-[2-((3-(4- bromophenyl)-2-propenyl)-amino)-ethyl]-5-isoquinolinesulfonamide), abolished the enhancement of GJIC by colforsin and IBMX but did not abolish that by isoproterenol.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Research Laboratories, Nippon Shinyaku Co. Ltd., Kyoto, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Ueda
authors.forename: Y
authors.initials: Y
authors.lastname: Kameda
authors.forename: O
authors.initials: O
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Shibata
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002450:Cell Communication / Q000187:drug effects; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology*; D005753:Gastric Mucosa / Q000166:cytology* / Q000187:drug effects; D007545:Isoproterenol / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D009550:Nigericin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011817:Rabbits; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D013449:Sulfonamides
chemical_list: D007546:Isoquinolines; D011943:Receptors, Adrenergic, beta; D013449:Sulfonamides; D000584:Amiloride; D011433:Propranolol; D000242:Cyclic AMP; D007545:Isoproterenol; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D009550:Nigericin; D015056:1-Methyl-3-isobutylxanthine