川芎嗪舒血管作用的部位差异性及其对钙释放的抑制

川芎嗪(TMP, 0.01-2.0 mmol·L^-1)呈浓度依赖性地舒张犬的多种离体血管条， 其中舒张股动脉的强度是冠状动脉的3.3倍；在肠系膜动脉, TMP对前列腺素F_2α及高浓度KCl预收缩的动脉条均有舒张作用，但对前者的作用强度约为后者的5.6倍；在无Ca²⁺液中，TMP呈浓度依赖性地抑制苯福林的缩血管作用而不影响咖啡因的效应. 结果表明：(1)TMP的扩血管作用具有部位差异性; (2)TMP不具备典型钙拮抗剂的特点; (3)TMP可能对受体中介的钙释放有一定的选择性抑制.

Regional difference of tetramethylpyrazine in vasorelaxation and its inhibitory effect on Ca2+-release

The vasorelaxing effects of tetramethylpyr azine (TMP) were tested in dog isolated mesenteric, femoral, coronary, renal and basilar artery strips precontracted with pros- taglandin F_2α (PGF_2α 0.5 μmol·L^-1). The results showed that TMP was 3.3-fold as potent in fem-oral artery as in coronary artery. In mesenteric artery, it was 5.6 fold as potent in the strips precontracted with PGF_2α as with KCl 20 mmol·L^-1. Furthermore, TMP inhibited the contractions induced by phenylephrine but not caffeine in Ca²⁺-free medium. From the results three proposals are suggested: (1) there may be a regional difference in the vasorelaxant effects of TMP; (2) TMP may not be a calcium blocker; (3) TMP may interference with receptor-mediated Ca²⁺ release.