title: Two distinct effects of 12S-hydroxyeicosatetraenoic acid on platelet aggregation by zooxanthellatoxin-A and ionomycin.
abstract: The marine toxin zooxanthellatoxin-A (ZT-A) and the Ca2+ ionophore ionomycin caused aggregation in rabbit platelets. While ZT-A-induced platelet aggregation was inhibited by indomethacin, ionomycin-induced aggregation was potentiated by the drug. In contrast, both ZT-A- and ionomycin-induced accumulations of thromboxane B2 (TXB2), a stable metabolite of thromboxane A2 (TXA2), were completely inhibited by indomethacin. 12S-Hydroxyeicosatetraenoic acid (12-HETE), which could be accumulated in the presence of indomethacin, inhibited ZT-A-induced aggregation, but it potentiated the ionomycin-induced one. These results suggest that the different effects of indomethacin may be attributed to the distinct effects of 12-HETE on ZT-A- and ionomycin-induced platelet aggregations.
authors.affiliation: Department of Pharmaceutical Molecular Biology, Faculty of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
authors.forename: M C
authors.initials: MC
authors.lastname: Rho
authors.forename: N
authors.initials: N
authors.lastname: Nakahata
authors.forename: Y
authors.initials: Y
authors.lastname: Ohizumi
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000494:pharmacology*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D004347:Drug Interactions; D007213:Indomethacin / Q000494:pharmacology*; D015759:Ionomycin / Q000037:antagonists & inhibitors; D007476:Ionophores / Q000037:antagonists & inhibitors; D008387:Marine Toxins / Q000037:antagonists & inhibitors; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011090:Polyenes / Q000037:antagonists & inhibitors; D011817:Rabbits; D013928:Thromboxane A2 / Q000097:blood; D013929:Thromboxane B2 / Q000097:blood
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007476:Ionophores; D008387:Marine Toxins; D010975:Platelet Aggregation Inhibitors; D011090:Polyenes; C081400:zooxanthellatoxin A; D013929:Thromboxane B2; D015759:Ionomycin; D013928:Thromboxane A2; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D007213:Indomethacin