%0 Journal Article %1 Hayn2009 %A von Hayn, K. %A Werthmann, R. C. %A Nikolaev, V. O. %A Hommers, L. G. %A Lohse, M. J. %A Bunemann, M. %D 2009 %J Am J Physiol Cell Physiol %K imported %T Gq-mediated Ca2+ signals inhibit adenylyl cyclases 5/6 in vascular smooth muscle cells %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19889965 %X Cyclic AMP and Ca(2+) are antagonistic intracellular messengers for the regulation of vascular smooth muscle tone: rising levels of Ca(2+) lead to vasoconstriction, while an increase of cAMP induces vasodilatation. Here we investigated whether Ca(2+) interferes with cAMP signaling by regulation of phophodiesterases (PDEs) or adenylyl cyclases (ACs). We studied regulation of cAMP concentrations by Ca(2+) signals evoked by endogenous purinergic receptors in vascular smooth muscle cells (VSMCs). The fluorescence resonance energy transfer (FRET)-based cAMP sensor Epac1-camps allowed the measurement of cAMP levels in single living VSMCs with subsecond temporal resolution. Moreover, in-vitro calibration of Epac1-camps enabled us to estimate the absolute cytosolic cAMP concentrations. Stimulation of purinergic receptors decreased cAMP levels in the presence of the beta-adrenergic agonist isoproterenol. Simultaneous imaging of cAMP with Epac1-camps and of Ca(2+) with Fura 2 revealed a rise of intracellular Ca(2+) in response to purinergic stimulation followed by a decline of cAMP. Chelation of intracellular Ca(2+) and overexpression of Ca(2+)-independent AC4 antagonized this decline of cAMP while pharmacological inhibition of Ca(2+)-activated PDE1 had no effect. Adenylyl cyclase assays with VSMC membranes revealed a significant attenuation of isoproterenol-stimulated cAMP production by the presence of 2 muM Ca(2+). Furthermore, siRNA knockdown of AC5 and AC6 (the two adenylyl cyclases known to be inhibited by Ca(2+)), significantly reduced the decrease of cAMP upon purinergic stimulation of isoproterenol-prestimulated VSMCs. Taken together, these results implicate a Ca(2+)-mediated inhibition of AC5 and 6 as an important mechanism of purinergic receptor-induced decline of cAMP and show a direct cross talk of these signaling pathways in VSMCs.

@article{Hayn2009, abstract = {Cyclic AMP and Ca(2+) are antagonistic intracellular messengers for the regulation of vascular smooth muscle tone: rising levels of Ca(2+) lead to vasoconstriction, while an increase of cAMP induces vasodilatation. Here we investigated whether Ca(2+) interferes with cAMP signaling by regulation of phophodiesterases (PDEs) or adenylyl cyclases (ACs). We studied regulation of cAMP concentrations by Ca(2+) signals evoked by endogenous purinergic receptors in vascular smooth muscle cells (VSMCs). The fluorescence resonance energy transfer (FRET)-based cAMP sensor Epac1-camps allowed the measurement of cAMP levels in single living VSMCs with subsecond temporal resolution. Moreover, in-vitro calibration of Epac1-camps enabled us to estimate the absolute cytosolic cAMP concentrations. Stimulation of purinergic receptors decreased cAMP levels in the presence of the beta-adrenergic agonist isoproterenol. Simultaneous imaging of cAMP with Epac1-camps and of Ca(2+) with Fura 2 revealed a rise of intracellular Ca(2+) in response to purinergic stimulation followed by a decline of cAMP. Chelation of intracellular Ca(2+) and overexpression of Ca(2+)-independent AC4 antagonized this decline of cAMP while pharmacological inhibition of Ca(2+)-activated PDE1 had no effect. Adenylyl cyclase assays with VSMC membranes revealed a significant attenuation of isoproterenol-stimulated cAMP production by the presence of 2 muM Ca(2+). Furthermore, siRNA knockdown of AC5 and AC6 (the two adenylyl cyclases known to be inhibited by Ca(2+)), significantly reduced the decrease of cAMP upon purinergic stimulation of isoproterenol-prestimulated VSMCs. Taken together, these results implicate a Ca(2+)-mediated inhibition of AC5 and 6 as an important mechanism of purinergic receptor-induced decline of cAMP and show a direct cross talk of these signaling pathways in VSMCs.}, added-at = {2010-12-14T18:12:02.000+0100}, author = {von Hayn, K. and Werthmann, R. C. and Nikolaev, V. O. and Hommers, L. G. and Lohse, M. J. and Bunemann, M.}, biburl = {https://www.bibsonomy.org/bibtex/29facfede2d6c2ab9bf332cbe8aed6ccc/pharmawuerz}, endnotereftype = {Journal Article}, interhash = {f84ea13f6d9c8638cda1b75eafb327dc}, intrahash = {9facfede2d6c2ab9bf332cbe8aed6ccc}, issn = {1522-1563 (Electronic) 1522-1563 (Linking)}, journal = {Am J Physiol Cell Physiol}, keywords = {imported}, month = {Nov 4}, note = {Journal article American journal of physiology. Cell physiology Am J Physiol Cell Physiol. 2009 Nov 4.}, shorttitle = {Gq-mediated Ca2+ signals inhibit adenylyl cyclases 5/6 in vascular smooth muscle cells}, timestamp = {2010-12-14T18:12:13.000+0100}, title = {Gq-mediated Ca2+ signals inhibit adenylyl cyclases 5/6 in vascular smooth muscle cells}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19889965}, year = 2009 }