title: Role of calcium and calmodulin in ciliary stimulation induced by acetylcholine.
abstract: The goal of this work was to elucidate the molecular events underlying stimulation of ciliary beat frequency (CBF) induced by acetylcholine (ACh) in frog esophagus epithelium. ACh induces a profound increase in CBF and in intracellular Ca(2+) concentration ([Ca(2+)](i)) through M(1) and M(3) muscarinic receptors. The [Ca(2+)](i) slowly decays to the basal level, while CBF stabilizes at an elevated level. These results suggest that ACh triggers Ca(2+)-correlated and -uncorrelated modes of ciliary stimulation. ACh response is abolished by the phospholipase C (PLC) inhibitor U-73122 and by depletion of intracellular Ca(2+) stores but is unaffected by reduction of extracellular Ca(2+) concentration and by blockers of Ca(2+) influx. Therefore, ACh activates PLC and mobilizes Ca(2+) solely from intracellular stores. The calmodulin inhibitors W-7 and calmidazolium attenuate the ACh-induced increase in [Ca(2+)](i) but completely abolish the elevation in CBF. Therefore, elevation of [Ca(2+)](i) is necessary for CBF enhancement but does not lead directly to it. The combined effect of Ca(2+) elevation and of additional factors, presumably mobilized by Ca(2+)-calmodulin, results in a robust CBF enhancement.
authors: Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors: O
authors: O
authors: Zagoory
authors: A
authors: A
authors: Braiman
authors: L
authors: L
authors: Gheber
authors: Z
authors: Z
authors: Priel
mesh_terms: D000109:Acetylcholine / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000187:drug effects* / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D002923:Cilia / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004848:Epithelium / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D004947:Esophagus / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D007093:Imidazoles / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D011895:Rana ridibunda; D011976:Receptors, Muscarinic / Q000187:drug effects* / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology; D014268:Trifluoperazine / Q000494:pharmacology
chemical_list: D002147:Calmodulin; D004791:Enzyme Inhibitors; D007093:Imidazoles; D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D013449:Sulfonamides; D014268:Trifluoperazine; C031938:calmidazolium; C017967:W 7; D000109:Acetylcholine; D002118:Calcium