title: Activation of the cyclic AMP pathway promotes serotonin-induced Ca2+ oscillations in salivary glands of the blowfly Calliphora vicina.
abstract: Ca(2+) and cAMP signalling pathways interact in a complex manner at multiple sites. This crosstalk fine-tunes the spatiotemporal patterns of Ca(2+) and cAMP signals. In salivary glands of the blowfly Calliphora vicina fluid secretion is stimulated by serotonin (5-hydroxytryptamine, 5-HT) via activation of two different 5-HT receptors coupled to the InsP(3)/Ca(2+) (Cv5-HT(2α)) or the cAMP pathway (Cv5-HT(7)), respectively. We have shown recently in permeabilized gland cells that cAMP sensitizes InsP(3)-induced Ca(2+) release to InsP(3). Here we study the effects of the cAMP signalling pathway on 5-HT-induced oscillations in transepithelial potential (TEP) and in intracellular [Ca(2+)]. We show: (1) Blocking the activation of the cAMP pathway by cinanserin suppresses the generation of TEP and Ca(2+) oscillations, (2) application of 8-CPT-cAMP in the presence of cinanserin restores 5-HT-induced TEP and Ca(2+) oscillations, (3) 8-CPT-cAMP sensitizes the InsP(3)/Ca(2+) signalling pathway to 5-HT and the Cv5-HT(2α) receptor agonist 5-MeOT, (4) 8-CPT-cAMP induces Ca(2+) oscillations in cells loaded with subthreshold concentrations of InsP(3), (5) inhibition of protein kinase A by H-89 abolishes 5-HT-induced TEP and Ca(2+) spiking and mimics the effect of cinanserin. These results suggest that activation of the cyclic AMP pathway promotes the generation of 5-HT-induced Ca(2+) oscillations in blowfly salivary glands.
authors.affiliation: Institute of Biochemistry and Biology, Department of Animal Physiology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany.
authors.forename: Lennart
authors.initials: L
authors.lastname: Fechner
authors.forename: Otto
authors.initials: O
authors.lastname: Baumann
authors.forename: Bernd
authors.initials: B
authors.lastname: Walz
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002928:Cinanserin / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004175:Diptera / Q000502:physiology*; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D015544:Inositol 1,4,5-Trisphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D007546:Isoquinolines / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D044402:Receptor, Serotonin, 5-HT2A / Q000378:metabolism; D012469:Salivary Glands / Q000187:drug effects* / Q000378:metabolism; D012701:Serotonin / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
chemical_list: D007546:Isoquinolines; D044402:Receptor, Serotonin, 5-HT2A; D013449:Sulfonamides; D013873:Thionucleotides; C086878:inositol 1,4,6-trisphosphate; D012701:Serotonin; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D015544:Inositol 1,4,5-Trisphosphate; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D002928:Cinanserin; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D002118:Calcium