title: Lack of evidence for a role for the lipoxygenase pathway in increases in cytosolic calcium evoked by ADP and arachidonic acid in human platelets.
abstract: We have investigated the possibility that metabolism of arachidonic acid by the lipoxygenase pathway contributes to ADP-evoked rises in [Ca2+], in human platelets. 30 microM BW A4C did not affect ADP-evoked Ca2+ signals, but inhibited 12-lipoxygenase activity in platelet homogenates. Another lipoxygenase inhibitor, MK 866 was similarly without effect on ADP-evoked Ca2+ signals. ADP was found to liberate little arachidonic acid, and formation of the lipoxygenase product 12-HETE was not detectable. The rise in [Ca2+]i evoked by arachidonic acid was completely inhibited by the cyclooxygenase inhibitors aspirin or indomethacin. These results indicate that lipoxygenase products do not play an essential role in mediating rises in [Ca2+]i evoked by ADP, or by arachidonic acid.
authors.affiliation: Physiological Laboratory, University of Cambridge, UK.
authors.forename: R R
authors.initials: RR
authors.lastname: Vindlacheruvu
authors.forename: T J
authors.initials: TJ
authors.lastname: Rink
authors.forename: S O
authors.initials: SO
authors.lastname: Sage
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism*; D000345:Affinity Labels; D016718:Arachidonic Acid / Q000378:metabolism*; D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors; D003600:Cytosol / Q000378:metabolism*; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D016257:Fura-2 / Q000737:chemistry; D006801:Humans; D008084:Lipoxygenase / Q000378:metabolism*; D016859:Lipoxygenase Inhibitors
chemical_list: D000345:Affinity Labels; D016861:Cyclooxygenase Inhibitors; D016859:Lipoxygenase Inhibitors; D016718:Arachidonic Acid; D004533:Egtazic Acid; D000244:Adenosine Diphosphate; D008084:Lipoxygenase; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium; D016257:Fura-2