title: cAMP reduces the affinity of Ca2+-triggered secretion in platelets.
abstract: Prostacyclin and other related compounds known to increase intracellular cAMP levels inhibit platelet responses. The mechanisms involved are only partially known, especially those concerning the complex relations between Ca2+ and cAMP as opposite intracellular mediators. Here, we have investigated aggregation and secretion in quin2-loaded platelets under conditions in which Ca2+ and cAMP are the only intracellular mediators. Our results show that cAMP inhibits aggregation and secretion in ionophore-treated cell without modifying their intracellular Ca2+ levels. This result suggests that the inhibition takes place on some intracellular target for Ca2+.
mesh_terms: D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology*; D004987:Ethers / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects*; D006801:Humans; D015759:Ionomycin; D010974:Platelet Aggregation / Q000187:drug effects; D012636:Secretory Rate / Q000187:drug effects
chemical_list: D004987:Ethers; D005576:Colforsin; D015759:Ionomycin; D000242:Cyclic AMP; D002118:Calcium