Bushfield M, McNicol A, MacIntyre D E
Biochem J. 1987 Feb 1;241(3):671-6. doi: 10.1042/bj2410671.
Vasopressin and adrenaline in combination exert synergistic effects on platelet activity. This study investigated the effects of sub-threshold concentrations of adrenaline (0.1-1 microM) on vasopressin (10 nM-1 microM)-induced platelet aggregation, ATP secretion, elevation of cytosolic free Ca2+ concentration ([Ca2+]i) and hydrolysis of inositol phospholipids, monitored as [32P]phosphatidic acid formation. Potentiation of vasopressin-induced aggregation and ATP secretion by adrenaline was accompanied by enhanced elevation of [Ca2+]i and [32P]phosphatidic acid formation. The stimulatory effects of adrenaline on vasopressin-induced platelet activation were mimicked by the combination of the Ca2+ ionophore, ionomycin, and the protein kinase C activator, phorbol 12-myristate 13-acetate, but not by either of these agents alone. These results suggest that the potentiation of vasopressin-induced platelet activation by adrenaline is mediated via enhancement of inositol phospholipid hydrolysis and elevation of [Ca2+]i.
血管加压素和肾上腺素联合使用对血小板活性具有协同作用。本研究调查了亚阈值浓度的肾上腺素（0.1 - 1微摩尔）对血管加压素（10纳摩尔 - 1微摩尔）诱导的血小板聚集、ATP分泌、胞质游离钙离子浓度（[Ca2+]i）升高以及肌醇磷脂水解（以[32P]磷脂酸形成来监测）的影响。肾上腺素增强血管加压素诱导的聚集和ATP分泌的同时，伴随着[Ca2+]i和[32P]磷脂酸形成的增强。钙离子载体离子霉素和蛋白激酶C激活剂佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯联合使用可模拟肾上腺素对血管加压素诱导的血小板活化的刺激作用，但单独使用这两种试剂均无此作用。这些结果表明，肾上腺素增强血管加压素诱导的血小板活化是通过增强肌醇磷脂水解和升高[Ca2+]i介导的。
