Burns G B, Dodge J A
Agents Actions. 1984 Jan;14(1):102-8. doi: 10.1007/BF01966841.
Theophylline (0.05-1.0 mM) greatly enhanced the inhibition of platelet aggregation by prostaglandin E1 and at higher concentrations (1.0-4.0 mM) theophylline alone inhibited platelet aggregation, by a mechanism which did not involve significant changes in platelet cAMP levels. These concentrations of theophylline and theophylline in combination with prostaglandin E1, inhibited the synthesis of thromboxane A2, prostaglandin E2 and F2a in stimulated platelets. Theophylline also inhibited arachidonic acid-stimulated platelet aggregation suggesting an effect on cyclooxygenase activity. The calcium ionophore A23187 prevented and reversed the inhibition of platelet aggregation by theophylline, suggesting that theophylline inhibits the rise in intracellular calcium levels which occurs in response to the synthesis of prostaglandin endoperoxides and thromboxane A2.
茶碱(0.05 - 1.0 mM)显著增强了前列腺素E1对血小板聚集的抑制作用,且在较高浓度(1.0 - 4.0 mM)时,茶碱单独就能抑制血小板聚集,其机制并不涉及血小板环磷酸腺苷(cAMP)水平的显著变化。这些浓度的茶碱以及茶碱与前列腺素E1联合使用时,可抑制受刺激血小板中血栓素A2、前列腺素E2和F2α的合成。茶碱还抑制花生四烯酸刺激的血小板聚集,提示其对环氧化酶活性有影响。钙离子载体A23187可预防并逆转茶碱对血小板聚集的抑制作用,这表明茶碱抑制了因前列腺素内过氧化物和血栓素A2合成而导致的细胞内钙水平升高。