| Abstract: | The antagonistic effects of trans-2,6- bis-(3,4-dimethoxyphenyl)-tetrahydro-(4H) pyran (SZ-1) and trans-2-(3,4,5-trimethoxyphenyl)-6-(2,4-difluoro- phenyl)-tetrahydro-(4H)pyran (DFTM) on rabbit platelet aggregation, DNA synthesis and proliferation of bovine cerebromicrovascular smooth muscle cells (BCSMC) induced by platelet activating factor (PAF) were investigated. The results showed that PAF strongly stimulated rabbit platelet aggregation and at 1.91 μmol·L -1 the stimulatory rate is 71.7%. Both drugs inhibited PAF-induced rabbit platelets aggregation in a dose-dependent manner and their IC 50s were 0.39 and 0.84 nmol·L -1 , respectively for SZ-1 and DFTM. Also, PAF significantly stimulated the proliferation of BCSMC and reached maximal effect at 48 h at 0.1 nmol·L -1 . SZ-1 and DFTM at 1 nmol·L -1 inhibited PAF-induced proliferation of BCSMC by 25.9% and 30.7%, respectively. PAF meanwhile promoted the DNA synthesis of BCSMC and SZ-1, DFTM, at 1 nmol·L -1 inhibited PAF-induced DNA synthesis by 29.1% and 24.4%, respectively. The results indicate that PAF stimulating platelet aggregation and the proliferation of BCSMC might be one of the events which PAF contributes to the pathogenesis of cerebral atherosclerosis. SZ-1 and DFTM might have a potential application in the prevention and treatment of cerebrovascular disorders. |
