Objective To explore the effects of chloride channels on the regulation of platelet cytoplasmic free calcium concentration
(\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 \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 \i. As compared with the control group, DIDS, SK&F96365 and Nifedipine could significantly reduce the PAG, Ca 2+ release and Ca 2+ influx in thrombin activated platelet (P<0.05). The combination of DIDS and SK&F96365 had greater effects in reducing the PAG, Ca 2+ release and Ca 2+ influx than either reagent alone(P<0.05). The combination of DIDS and nifedipine also had greater effect than each alone in reducing Ca 2+ release (P<0.05). The combination of NFA and SK&F96365 weakened each other’s effect on Ca 2+ release (P<0.05), while NFA and nifedipine weakened each other’s effects on PAG, Ca 2+ release and Ca 2+ influx in thrombin activated platelet (P<0.05). Conclusion DIDS and NFA have no effect on the resting \i and the leak calcium influx of platelet. DIDS can inhibit the Ca 2+ release, Ca 2+ influx and PAG of platelet induced by thrombin, while NFA can only inhibit the Ca 2+ release. The chloride channel and calcium channel blockers have interactions in affecting resting \i and PAG of platelet. The opening of chloride channel can influence the cellular calcium movement of platelet.