静脉注射内吗啡肽对麻醉大鼠左心室功能的影响

摘要

Objective:To observe the effects of intravenous injection of endomorphin-1(EM-1) and endomorphin-2(EM-2) on the left ventricular function in anesthetized rats,and to primarily investigate its potential mechanism.Methods:The left ventricular function(LVSP,HR, ±dp/dt) were measured by inserting a catheter from right carotid artery into left ventricle after intravenous injection of EM-1 and EM-2 in the anesthetized rats.Results:Compared with control group,EM-1 and EM-2 led to decreased dose-dependent for the left ventricular function.By comparison with EM +NS group,the decrease in left ventricular function was attenuated by pretreatment with intravenous injection of either naloxone(1 mg/kg,i.v.),atropine(50 μg/kg,i.v.),L-NNA(25 mg/kg,i.v.) or bilateral cervical vagotomy.Conclusion:Intravenous administration of EM-1 and EM-2 produced inhibition effect on the left ventricular function in anesthetized rats,and the potential mechanism is associated with mediation of opioid receptor,involvement of M-cholinoceptor and NO as well as vagus nerve excitation.%目的：观察静脉注射内吗啡肽－1和2（EM－1、EM－2）对大鼠左心室功能的影响，并初步探讨其作用机理。方法：大鼠麻醉后，经右颈总动脉左心室插管测左心室功能（ LVSP、HR、±dp／dt等）。颈外静脉注射给药。结果：与对照组比较，静脉注射EM－1、EM－2剂量依赖性地降低麻醉大鼠左心室功能。与EM－1／EM－2＋NS组比较，除一氧化氮合成酶抑制剂 L－NNA （25 mg／kg，i．v．）对EM－1降低心率的作用无明显影响外，预先给予纳洛酮（1 mg／kg，i．v．）或阿托品（50μg／kg，i．v．）或L－NNA （25 mg／kg，i．v．），或切断双侧迷走神经均显著减弱EM－1、EM－2降低心功能的作用（P＜0．05或P＜0．01）。结论：静脉注射EM－1、EM－2可引起麻醉大鼠左心室功能下降，此效应由阿片受体介导，有胆碱能M受体参加，有NO的参与，与迷走神经兴奋有关。