氯通道阻断剂对血小板胞浆游离钙和血小板聚集的影响

目的　探讨氯通道在血小板胞浆游离钙和血小板聚集功能调节中的作用。方法　新鲜分离人血小板,以凝血酶为诱导剂,观察氯通道阻断剂DIDS、NFA和钙通道阻断剂SK&F96365、Nife dipine对血小板胞浆游离钙和血小板聚集的单独作用和相互作用。结果　氯通道阻断剂DIDS、NFA可以浓度依赖性地抑制凝血酶 ( 1U/ml)诱导的血小板聚集,对静息血小板胞浆游离钙无明显影响;DIDS、SK&F96365、Nifedipine可以明显降低凝血酶诱导的血小板聚集、钙释放和钙内流,与对照组比较,P<0. 05;DIDS与SK&F96365联合,对凝血酶诱导的血小板聚集、钙释放和钙内流的抑制比各自单独抑制作用明显增高(P<0. 05),两者的作用相互增强;DIDS与Nifedipine联合,对凝血酶诱导的血小板钙释放的抑制比各自单独抑制作用明显增高 (P<0. 05 ),两者可相互增强;NFA与SK&F96365联合,对凝血酶诱导的血小板钙释放的抑制比各自的单独作用明显降低 (P<0. 05 ),两者可相互减弱;NFA与Nifedipine联合,对凝血酶诱导的血小板聚集、钙释放和钙内流的抑制比各自的单独作用明显降低(P<0. 05),两者可相互减弱。结论　氯通道阻断剂DIDS、NFA对人静息血小板胞浆钙浓度无影响;DIDS可抑制凝血酶诱导的血小板聚集、钙释放和钙内流,NFA仅抑制凝血酶诱导的钙释放;氯通道阻断剂和

The effects of chloride channel blockers on thrombocytic cytoplasmic free calcium concentration and platelet aggregation

OBJECTIVE: To explore the effects of chloride channels on the regulation of platelet cytoplasmic free calcium concentration ([Ca2+]i) and platelet aggregation (PAG). METHODS: Freshly separated platelets were activated by thrombin. Chloride channel blockers DIDS or NFA and calcium channel blockers SK&F96365 or nifedipine were added to study the effects on platelet [Ca2+]i and PAG by a single reagent or the combination of reagents and find out the interactions among DIDS, NFA, SK&F96365 and nifedipine. RESULTS: Both DIDS and NFA could inhibit the thrombin (1 U/ml) induced PAG in a dose-dependent manner, whereas had little effect on resting [Ca2+]i. As compared with the control group, DIDS, SK&F96365 and Nifedipine could significantly reduce the PAG, Ca2+ release and Ca2+ influx in thrombin activated platelet (P < 0.05). The combination of DIDS and SK&F96365 had greater effects in reducing the PAG, Ca2+ release and Ca2+ influx than either reagent alone (P < 0.05). The combination of DIDS and nifedipine also had greater effect than each alone in reducing Ca2+ release (P < 0.05). The combination of NFA and SK&F96365 weakened each other's effect on Ca2+ release (P < 0.05), while NFA and nifedipine weakened each other's effects on PAG, Ca2+ release and Ca2+ influx in thrombin activated platelet (P < 0.05). CONCLUSION: DIDS and NFA have no effect on the resting [Ca2+]i and the leak calcium influx of platelet. DIDS can inhibit the Ca2+ release, Ca2+ influx and PAG of platelet induced by thrombin, while NFA can only inhibit the Ca2+ release. The chloride channel and calcium channel blockers have interactions in affecting resting [Ca2+]i and PAG of platelet. The opening of chloride channel can influence the cellular calcium movement of platelet.