Vargish T, Beamer K C, Daly T, Riggs T R
Department of Surgery, West Virginia University, School of Medicine, Morgantown 26506.
Circ Shock. 1987;23(3):189-95.
In previous work, morphine sulfate was shown to decrease heart rate (HR) and cardiac output (CO) in a dose-related fashion. It was hypothesized that this effect was mediated by opiate receptors located in the myocardium. The present study evaluated the effect of opiate receptor antagonism with naloxone using a modified Langendorff rat heart perfusion apparatus. Sixty-five rat hearts were excised and perfused with Krebs-Henseleit buffer (KHB) solution, to which morphine sulfate and naloxone (NAL) were added in different concentrations. In the initial studies, NAL (10(-5) M) was added to the perfusate prior to the incremental additions of morphine. This resulted in no antagonism of the previously described opiate agonist effects. Norepinephrine (NE; 10(-9) M) was then added to the perfusate prior to the NAL or morphine. The NE did not affect the dose-related decrease in HR and CO when morphine was added but did permit the attenuation of the morphine effect by the addition of increasing concentrations of NAL up to 10(-5) M. These results suggest that the agonist effect can be attenuated by opiate receptor antagonism with NAL; the data also suggest a possible interrelationship between opiate and catecholamine receptor activity in the myocardium.
在先前的研究中，硫酸吗啡被证明可呈剂量相关方式降低心率（HR）和心输出量（CO）。据推测，这种作用是由位于心肌中的阿片受体介导的。本研究使用改良的Langendorff大鼠心脏灌注装置评估了纳洛酮对阿片受体的拮抗作用。切除65只大鼠的心脏，并用Krebs-Henseleit缓冲液（KHB）溶液灌注，向其中加入不同浓度的硫酸吗啡和纳洛酮（NAL）。在最初的研究中，在递增添加吗啡之前，先向灌注液中加入NAL（10^(-5) M）。这并未对先前描述的阿片激动剂作用产生拮抗作用。然后在加入NAL或吗啡之前，向灌注液中加入去甲肾上腺素（NE；10^(-9) M）。当加入吗啡时，NE并未影响HR和CO的剂量相关降低，但当加入浓度高达10^(-5) M的递增浓度的NAL时，确实使吗啡的作用减弱。这些结果表明，阿片受体拮抗作用可通过NAL减弱激动剂作用；数据还表明心肌中阿片和儿茶酚胺受体活性之间可能存在相互关系。
