Riggs T R, Yano Y, Vargish T
Circ Shock. 1986;19(1):31-8.
A modified Langendorff rat heart preparation with an isolated working rat heart was used to establish the presence of opiate receptors in the myocardium and to demonstrate the effects of an opiate agonist on myocardial function in the absence of neuronal and humoral factors. Twenty-five Sprague-Dawley rats weighing 400-500 gm were anesthetized and had their hearts excised and attached to the Langendorff perfusion apparatus. After a 30 min control period, the Krebs-Henseleit Buffer (KHB) perfusion solution was altered by the addition of 0.9% NaCl (S) or morphine sulfate (MS), which resulted in a final concentration of 2 X 10(-4) M or 3 X 10(-4) M MS in the KHB. Temperature, preload, and afterload were kept constant while heart rate (HR), cardiac output (CO), and aortic dP/dtmax were measured. Significant dose-related depression of HR, CO, and less significantly, aortic dP/dtmax were demonstrated. The data suggest that opiate receptors are present in the myocardium and that morphine sulfate directly effects the myocardium causing a significant decrease in HR, CO, and aortic dP/dtmax. These changes are a result of opiate receptor agonism, which seems to be primarily a negative chronotropic effect and might explain the mechanism for the role of endogenous opiates during shock.
采用改良的Langendorff大鼠心脏制备方法，结合离体工作大鼠心脏，以确定心肌中阿片受体的存在，并在无神经和体液因素的情况下，证明阿片激动剂对心肌功能的影响。25只体重400 - 500克的Sprague-Dawley大鼠麻醉后，取出心脏并连接到Langendorff灌注装置上。在30分钟的对照期后，通过添加0.9%氯化钠（S）或硫酸吗啡（MS）改变Krebs-Henseleit缓冲液（KHB）灌注溶液，最终在KHB中的MS浓度为2×10⁻⁴ M或3×10⁻⁴ M。在保持温度、前负荷和后负荷恒定的同时，测量心率（HR）、心输出量（CO）和主动脉dP/dtmax。结果显示，HR、CO出现显著的剂量相关降低，主动脉dP/dtmax降低程度较小。数据表明心肌中存在阿片受体，硫酸吗啡直接作用于心肌，导致HR、CO和主动脉dP/dtmax显著降低。这些变化是阿片受体激动的结果，这似乎主要是一种负性变时作用，可能解释了内源性阿片在休克过程中作用的机制。
