Abstract: Effects of berberine (Ber) on platelet aggregation and TXB2 and 6-keto-PGF1a plasma levels were studied in rabbits with uncomplete cerebral ischemia. Ber inhibited uncomplete cerebral ischemic rabbit platelet aggregation triggered by collagen, ADP, and arachidonic acid (AA) with the IC50 of 0.15, 0.46, and 0.51 mg·ml^-1, respectively. In rabbits, Ber 25, or 50 mg·kg^-1 iv 30 min after uncomplete cerebral ischemia, restrained the collagen ADP- and AA- induced platelet aggregation determined 90 min later. With radioimmunoassay, we measured the thromboxane B2 (TXB2) and 6-ketoprostaglandin F1α (6-keto-PGF1α) contents in rabbit plasma. The results indicated that the TXB2 level in rabbit 120 min after uncomplete cerebral ischemia (921±539 pg·mL^-1) was higher than that (230±71 pg·mL^-1) in normal rabbits (P <0.01), but 6-keto-PGF1α level after ischemia (73±23 pg·ml^-1) was lower than that (262±988 pg·ml^-1) in normal rabbit. Ber (5, 25 or 50 mg·kg^-1) reduced obviously the plasma TXB2 level in rabbit with uncomplete cerebral ischemia (504±196, 386±174, or 272±183 vs 921±539 pg·ml^-1, respectively, P<0.01). We conclude that the decrease of TXB2 content is one of the possible mechanisms of Ber anti-cerebral ischemic effect

Key words: Berberine, Cerebral ischemia, Platelet aggregation, Thromboxane B2, 6-Ketoprostaglandin F1 alpha