Vial C, Hechler B, Léon C, Cazenave J P, Gachet C
INSERM U.311, ETSS, Strasbourg, France.
Thromb Haemost. 1997 Dec;78(6):1500-4.
Human platelets are thought to possess at least two subtypes of purinoceptor, one of which, coupled to G-proteins, could be the P2Y1 receptor (Leon et al. 1997). However, it has been suggested that the unique rapid calcium influx induced by ADP in platelets could involve P2X1 ionotropic receptors (MacKenzie et al. 1996) and the aim of this study was thus to investigate the presence of P2X purinoceptors in platelets and megakaryoblastic cells. Using PCR experiments, we found P2X1 mRNA to be present in human platelets and megakaryoblastic cell lines. In platelets, the selective P2X1 agonist alphabetaMeATP induced a rise in intracellular calcium only in the presence of external calcium and this effect was antagonized by suramin and PPADS. Repeated addition of alphabetaMeATP desensitized the P2X1 purinoceptor but only slightly affected the ADP response, while no calcium response to alphabetaMeATP was observed in megakaryoblastic cells. These results support the existence of functional P2X1 purinoceptors on human platelets and the presence of P2X1 transcripts in megakaryoblastic cell lines.
人们认为人类血小板至少拥有两种嘌呤受体亚型，其中一种与G蛋白偶联，可能是P2Y1受体（Leon等人，1997年）。然而，有人提出，ADP在血小板中诱导的独特快速钙内流可能涉及P2X1离子型受体（MacKenzie等人，1996年），因此本研究的目的是调查血小板和巨核母细胞中P2X嘌呤受体的存在情况。通过PCR实验，我们发现P2X1 mRNA存在于人类血小板和巨核母细胞系中。在血小板中，选择性P2X1激动剂αβMeATP仅在存在细胞外钙的情况下才会引起细胞内钙升高，而这种效应被苏拉明和PPADS拮抗。重复添加αβMeATP会使P2X1嘌呤受体脱敏，但仅轻微影响ADP反应，而在巨核母细胞中未观察到对αβMeATP的钙反应。这些结果支持人类血小板上存在功能性P2X1嘌呤受体以及巨核母细胞系中存在P2X1转录本。
