氟苯桂嗪对Bay　K_（8644）等激动剂诱导的大鼠主动脉收缩的抑制作用

The inhibiory effect of Flunarizine on calcium agonists-evoked contraction on rat aorta

研究氟苯桂嗪对大鼠主动脉平滑肌收缩作用表明：氟苯桂嗪可以阻断由ＢａｙＫ８６４４、去甲肾上腺素及高钾去极化引起的大鼠主动脉收缩作用，并且其作用为非竞争性抑制。去甲肾上腺素引起的钙内流可以被氟苯桂嗪所阻断，其ＩＣ５０值为：７×１０－７ｍｏｌ·Ｌ－１阻断去极化引起的收缩反应，在高钾２ｍｉｎ及３５ｍｉｎ时其ＩＣ５０值分别为；４×１０－７ｍｏｌ·Ｌ－１，２．５×１０－８ｍｏｌ·Ｌ－１。氟苯桂嗪对以上三种物质所诱导的主动脉收缩的抑制作用的顺序为：高钾去极化＞ＢａｙＫ８６４４＞去甲肾上腺素。

Experments were performed on isolated rat aorta in order to examine the action of Flunarizine on norpinephrine. Bey K8644 and depolarization-induced。contractions. Rings of aorta were suspended in organ chambers filled with aerated physiological solution (37℃) for contineous isometric tension recordings.Norpinephrine-dependent Ca2+ influx was blocked by Flunarizine,the IC50 value was: 7 ×10-7 mol·L-1.Depolarization-dependent Ca2+ turnover blocked by Flunarizine, its IC50 value was: 2.5×10-8 mol·L-1.Bay K8644 induced contraction blocked by Flunarizine,the IC50 value was:1×10-7 mol·L-1. The results shown that Flunarizine caused an incompetitively inhibitory effects against three kinds of calcium agonists; the order of its effects was: depolarization>Bay K8644>norpinephrine.