Activation of the cyclic AMP pathway promotes serotonin-induced Ca2+ oscillations in salivary glands of the blowfly Calliphora vicina.

Lennart Fechner, Otto Baumann, Bernd Walz

Institute of Biochemistry and Biology, Department of Animal Physiology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany.

Cell calcium 2013 Feb

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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. Copyright © 2012 Elsevier Ltd. All rights reserved.

Citation

Lennart Fechner, Otto Baumann, Bernd Walz. Activation of the cyclic AMP pathway promotes serotonin-induced Ca2+ oscillations in salivary glands of the blowfly Calliphora vicina. Cell calcium. 2013 Feb;53(2):94-101