咪唑安定对大鼠血管可容性的影响及其机制研究(英文)

Effects and its involving mechanism of midazolam in Wistar rats vascular capacitance

目的 :研究咪唑安定对Wistar大鼠血管可容性的影响及其机制。方法 :全身容量血管的顺应性 (即可容性 )用平均循环充盈压 (Pmcf)表示 [Pmcf=VPP +K(FAP -VPP) ]。将所有实验Wistar大鼠分为 4个组 :对照组、六甲双胺预处理组、低血容量组及六甲双胺加去甲肾上腺素组。对 4组动物分别注入咪唑安定 0 .1、0 .3、0 .5、1mg·kg-1后 2min计算Pmcf。结果 :对照组、低血容量组、六甲双胺加去甲肾上腺素组注入咪唑安定后可导致平均动脉压 (MAP)显著下降 (P <0 .0 5 ) ,但只有对照组的MAP呈剂量依存性下降。对照组和低血容量组Pmcf呈剂量依存性下降 (P <0 .0 5 ) ,六甲双胺预处理组和六甲双胺加去甲肾上腺素组的Pmcf无改变。结论 :咪唑安定有剂量依存性扩张血管的作用 。

Objective To investigate the effects of midazolam in vascular capacitance and its involving mechanism in vivo.Methods The change of vascular capacitance was observed before and after midazolam infusion by measuring the mean circulatory filling pressure (P mcf).Wistar rats were assigned into four groups:an intact group,a sympathetic nervous system block group produced by hexamethonium infusion (SNSB),a SNSB+noradrenaline (NA) group,and a hypovolemic group.The P mcf was measured at a control state and 2 mins after a bolus administration of 0.1,0.3,0.5,and 1-mg·kg -1 of midazolam.Results The mean arterial pressure was decreased significantly by midazolam in intact,hypovolemic and SNSB+NA groups,compared to control levels( n=5-9,P<0.05),respectively.However,dose-dependent decreased MAP only showed in intact group.The P mcf decreased in intact and hypovolemic groups in a dose-dependent fashion (n=5-8,P< 0.05),but remained unchanged in the SNSB and SNSB+NA groups.Conclusion Midazolam causes venodialation in a dose-dependent fashion.This effect is primarily the result of an inhibition of sympathetic vasoconstrictor activity.