The effects of tetramethylpyrazine on the incidence of arrhythmias and the release of PGI2 and TXA2 in the ischemic rat heart.

Pretreatment with tetramethylpyrazine (TMP, 12 mg/kg/day), a drug originally derived from the rhizomes of Ligusticum wallichii, significantly reduced the incidence of ischemia-induced ventricular tachycardia (VT) and fibrillation (VF) from 100% and 50% of control hearts to 41% (p < 0.05) and 0% (p < 0.05), respectively, in the ischemic rat heart. TMP also diminished the incidence of reperfusion-induced VT and VF from 100% and 100% of control hearts to 33% (p < 0.05) and 41% (p < 0.05), respectively. Pretreatment with TMP produced a slight, but significant increase of 6-keto-PGF1 alpha and a decrease of TXB2 production during aerobic perfusion. Ischemia and reperfusion markedly increased the release of 6-keto-PGF1 alpha and TXB2. Pretreatment with TMP significantly enhanced the release of 6-keto-PGF1 alpha and diminished TXB2 outflow following left coronary artery occlusion and reperfusion.