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Cyclopiazonic acid(CPA) known as stimulating the release of intracellular calcium, aflatoxin B₁(AFB₁) causing gastrointestinal hemorrhage frequently were used as model toxic mycotoxins in these studies. First of all, the effects of various mycotoxins on the platelet aggregation response were determined. The effects of mycotoxins on the ATP release from platelet by aggregating factors were investigated. The results and conclusions obtained from these studies are : 1) CPA promoted ADP, collagen, thrombin, A.A. and PAF-induced rabbit platelet aggregation. AFB₁inhibited collagen, A.A. and PAF-induced rabbit platelet aggregation only. 2) CPA increased both aggregation and disaggregation time, whereas AFB₁decreased in a dose dependent manner. 3) CPA increased ADP, thrombin, A.A. and PAF-induced ATP release. AFB₁increased A.A.-induced ATP release and decreased PAF-induced release in a dose dependent manner. In conclusion, CPA promoted platelet aggregation by the increase of ATP. Antiaggregating effects of AFB1 may be due to decreases of ATP. These data provide the basis for the future study of roles of ATP release in platelet aggregation.
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