title: Histamine reduces gap junctional communication of human tonsil high endothelial cells in culture.
abstract: The regulation of gap junctional communication by histamine was studied in primary cultures of human tonsil high endothelial cells (HUTECs). We evaluated intercellular communication, levels, state of phosphorylation, and cellular distribution of gap junction protein subunits, mainly connexin (Cx)43. Histamine induced a time-dependent reduction in dye coupling (Lucifer yellow) associated with reduction in connexin43 localized at cell-cell appositions (immunofluorescence), without changes in levels and phosphorylation state of connexin43 (immunoblots). These effects were prevented with chlorpheniramine, an H1 receptor blocker; indomethacin, a cyclooxygenase blocker; or GF109203X, a protein kinase C inhibitor. Treatment with phorbol myristate acetate, a protein kinase C activator, and 4bromo (4Br)-A23187, a calcium ionophore, mimicked the histamine-induced effects on dye coupling. 8Bromo-cAMP doubled the dye coupling extent and prevented the histamine-induced reduction in incidence of dye coupling. After 24-h histamine treatment, known to desensitize H1 receptors, reapplication of histamine increased cell coupling in a way prevented by ranitidine, an H2 receptor blocker. Thus, activation of H1 and H2 receptors, which increase intracellular levels of free Ca2+ and cAMP, respectively, may affect gap junctional communication in opposite ways. Stabilization of actin filaments with phalloidine diminished but did not totally prevent histamine-induced cell shape changes and reduction in dye coupling. Hence, the histamine-induced reduction in gap junctional communication between HUTEC is mediated by cytoskeleton-dependent and -independent mechanisms and might contribute to modulate endothelial function in lymphoid tissue.
authors.affiliation: Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas, Pontificia Universidad, Católica de Chile, Chile.
authors.forename: Xavier F
authors.initials: XF
authors.lastname: Figueroa
authors.forename: Karina
authors.initials: K
authors.lastname: Alviña
authors.forename: Agustín D
authors.initials: AD
authors.lastname: Martínez
authors.forename: Gladys
authors.initials: G
authors.lastname: Garcés
authors.forename: Mario
authors.initials: M
authors.lastname: Rosemblatt
authors.forename: Mauricio P
authors.initials: MP
authors.lastname: Boric
authors.forename: Juan C
authors.initials: JC
authors.lastname: Sáez
mesh_terms: D002478:Cells, Cultured; D002744:Chlorpheniramine / Q000737:chemistry; D004396:Coloring Agents / Q000494:pharmacology; D018031:Connexin 43 / Q000737:chemistry; D000242:Cyclic AMP / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000166:cytology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017629:Gap Junctions; D006632:Histamine / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007211:Indoles / Q000494:pharmacology; D007213:Indomethacin / Q000737:chemistry; D007249:Inflammation; D007476:Ionophores / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D014066:Palatine Tonsil / Q000166:cytology*; D010590:Phalloidine / Q000737:chemistry; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
chemical_list: D004396:Coloring Agents; D018031:Connexin 43; D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D007211:Indoles; D007476:Ionophores; D008301:Maleimides; D010590:Phalloidine; D002744:Chlorpheniramine; D006632:Histamine; D000242:Cyclic AMP; D011493:Protein Kinase C; C070515:bisindolylmaleimide I; D013755:Tetradecanoylphorbol Acetate; D007213:Indomethacin