盐酸埃他卡林对大鼠主动脉血管环和尾动脉血管条的选择性舒张作用

Selective vasodilating action in rat aortic rings and tail artery str ips of ipta kalim hydrochloride

目的:研究抗高血压新药盐酸埃他卡林对大、小动脉舒张作用的药理学特性。方法:采用大鼠主动脉离体血管环和尾动脉血管条两种组织,对比观察盐酸埃他卡林对大、小动脉舒张作用的药理学特性,并且利用膜片钳技术观察盐酸埃他卡林对大鼠尾动脉平滑肌细胞钾电流的影响。结果:盐酸埃他卡林在1×10-7～1×10-3mol/L范围内对氯化钾预致收缩的大鼠尾动脉血管条产生剂量依赖性舒张反应,而对主动脉离体血管环却无明显的舒张反应,该作用能被ATP敏感性钾通道特异性拮抗剂格列苯脲阻断,并且能显著增强大鼠尾动脉平滑肌细胞的钾电流。结论:盐酸埃他卡林具有选择性舒张小动脉作用,具有ATP敏感性钾通道开放剂的主要药理学特征。

AIM:To study the pharmacological characteristics of vasodilating action in bi g artery and small artery of the novel antihypertensive drug iptakalim hydrochlo ride(Ipt). METHODS:Differences of the vasodilating action of Ipt in big artery and small artery were studied using isolated rat aortic rings and tail artery helical str ips,and the effects of Ipt on potassium currents in smooth muscle cells derived from rat tail artery were observed by using patch clamp technique. RESULTS:The vasodilating action of Ipt at 1× 10-7-1× 10-3 mol/L was o bserved in rat tail artery strips precontracted with potassium chloride in a con centration- dependent manner,but no significantly vasodilating effect was seen in rat aortic rings.And the action could be markedly antagonized by glibenclamid e,an inhibitor of ATP- sensitive potassium channels.Moreover,the potassium curr ents in smooth muscle cells derived from rat tail artery could be augmented by I pt. CONCLUSION:Iptakalim hydrochloride has a selective vasodilating action in sma ll artery,and it has major pharmacological characteristics of ATP- sensitive po tassium channel openers.