Hatmi M, Havet N, Vargaftig B B, Bachelet M
Unite de Pharmacologie Cellulaire, Institut Pasteur/INSERM n. 285, Paris, France.
Prostaglandins. 1992 May;43(5):457-72. doi: 10.1016/0090-6980(92)90128-g.
The effect of azelastine on intracellular cyclic AMP concentration and on various indexes of cell activation was evaluated in guinea-pig alveolar macrophages and in human platelets. The effect of azelastine was further investigated on adenylate cyclase activity using membranes and homogenates from guinea-pig alveolar macrophages. Pretreatment of alveolar macrophages with azelastine prevented the activation induced by PAF-acether and by the chemotactic peptide fMLP as estimated by the reduced liberation of arachidonic acid metabolites formed by the cyclooxygenase and the lipoxygenase pathways. The effect of azelastine was concentration-dependent (50 to 500 microM) and reversible. Similarly, a short pretreatment with azelastine (100 microM) prevented arachidonic acid-induced platelet aggregation. This effect was also reversible after washing the platelets. In guinea-pig alveolar macrophages, azelastine induced a concentration-dependent (10 to 500 microM) increase in intracellular cyclic AMP and markedly potentiated the increase induced by PGE2. In human platelets, azelastine alone increased intracellular cyclic AMP concentration marginally only but, as in the case of macrophages, synergized with PGI2. Azelastine did not activate significantly adenylate cyclase unless a cytosolic factor was included within the membrane fraction. This effect of azelastine was not due to Ca2+ movements and was not modified by GTP. Our findings show that azelastine interferes with cell activation through a mechanism related to an increase in intracellular cyclic AMP concentration. The increase in cyclic AMP was induced by azelastine in intact cells and in homogenates but not in a crude membrane fraction. Those results indicate that azelastine modifies a cytosolic factor that may be phosphodiesterase. In addition, similarities between the effects of azelastine and those of reference phosphodiesterase inhibitors (theophylline, isobutyl-methyl-xanthine) are shown in this study, suggesting that azelastine might behave as a phosphodiesterase inhibitor.
在豚鼠肺泡巨噬细胞和人血小板中评估了氮卓斯汀对细胞内环磷酸腺苷（cAMP）浓度及各种细胞活化指标的影响。使用豚鼠肺泡巨噬细胞的细胞膜和匀浆进一步研究了氮卓斯汀对腺苷酸环化酶活性的影响。用氮卓斯汀预处理肺泡巨噬细胞可防止由血小板活化因子（PAF - 乙酰醚）和趋化肽fMLP诱导的活化，这可通过环氧化酶和脂氧合酶途径形成的花生四烯酸代谢物释放减少来估计。氮卓斯汀的作用呈浓度依赖性（50至500微摩尔）且可逆。同样，用氮卓斯汀（100微摩尔）进行短时间预处理可防止花生四烯酸诱导的血小板聚集。洗涤血小板后这种作用也是可逆的。在豚鼠肺泡巨噬细胞中，氮卓斯汀诱导细胞内cAMP浓度呈浓度依赖性（10至500微摩尔）增加，并显著增强前列腺素E2（PGE2）诱导的增加。在人血小板中，单独的氮卓斯汀仅略微增加细胞内cAMP浓度，但与巨噬细胞情况一样，与前列环素（PGI2）协同作用。除非膜组分中包含胞质因子，否则氮卓斯汀不会显著激活腺苷酸环化酶。氮卓斯汀的这种作用不是由于钙离子移动，也不受鸟苷三磷酸（GTP）的影响。我们的研究结果表明，氮卓斯汀通过与细胞内cAMP浓度增加相关的机制干扰细胞活化。完整细胞和匀浆中氮卓斯汀可诱导cAMP增加，但粗制膜组分中则不然。这些结果表明氮卓斯汀可修饰一种可能是磷酸二酯酶的胞质因子。此外，本研究显示了氮卓斯汀与参考磷酸二酯酶抑制剂（茶碱、异丁基甲基黄嘌呤）作用之间的相似性，提示氮卓斯汀可能表现为一种磷酸二酯酶抑制剂。
