title: Relationship between cyclic AMP-dependent protein kinase activation and Ca uptake increase of sarcoplasmic reticulum fraction of hog biliary muscles relaxed by cholecystokinin-C-terminal peptides.
abstract: In hog terminal bile duct cholecystokinin peptides caused an activation of cyclic AMP-dependent protein kinase (A-PK) with cyclic AMP, followed by increase in Ca uptake of sarcoplasmic reticulum fraction (SR-F). By contrast, papaverine showed no activation of A-PK-induced Ca uptake by SR-F with cyclic AMP. The Ca uptake by SR-F was dependent on ATP and Mg2+, but the component phosphorylated was not the phosphoenzyme intermediate in Ca2+-ATPase. The effect of Ca uptake was blocked by the inclusion of a protein inhibitor of A-PK. The correlation coefficient between cyclic AMP-dependent SR-F phosphorylation and stimulated Ca uptake by the phosphorylated SR-F was 0.731 (P less than 0.01). These results suggest that one of the mechanisms by which CCK-4, CCK-8, and CCK-33 peptides relax isolated Oddi's sphincters of terminal bile ducts is activation of A-PK-induced Ca uptake by sarcoplasmic reticulum fraction and possibly also by plasma membrane.
mesh_terms: D000818:Animals; D001659:Biliary Tract / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002766:Cholecystokinin / Q000031:analogs & derivatives* / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D012844:Sincalide; D013552:Swine
chemical_list: D010446:Peptide Fragments; C025997:cholecystokinin (27-33); D002766:Cholecystokinin; D000242:Cyclic AMP; D011494:Protein Kinases; D012844:Sincalide; D002118:Calcium