急性心肌冬眠时心脏去甲肾上腺素的释放

目的：探讨急性心肌冬眠时心脏去甲肾上腺素的释放情况。方法：健康雄性SD大鼠36只，被随机分成对照组、冬眠组、冬眠-酪胺组、复灌组、复灌＋酪胺组和复灌＋去甲丙咪嗪＋酪胺组，每组6只。建立离体鼠心脏急性冬眠模型。用高效液相色谱法测定急性心肌冬眠时心脏去甲肾上腺素的自发性和电场刺激引起的释放．并评价去甲丙眯嗪和酪胺对去甲肾上腺素释放的影响及酪胺对心率的影响。结果：在冬眠组，缺血1min、120min和加入去甲丙咪嗪后冠脉流出液中去甲肾上腺素的含量分别为（1．9±0．5）．（2．0±0．4）和（1．9±0．4）pmol／g·min，三者之间差异没有显著性（P〉0．05）；电场刺激引起的心脏去甲肾上腺素的溢出在冬眠组为（3．2±1．3）pmol／g·min，对照组为（76．9±27．7）pmol／g·min，复灌组为（80．3±23．9）pmol／g·min，经方差分析。对照组和复灌组之间差异没有显著性（P〉0．05）。冬眠组较对照组以及复灌组显著减少（P〈0．01）；在冬眠-酪胺组和复灌＋酪胺组，酪胺均可引起心率和去甲肾上腺素溢出的明显增加（P〈0．05），而在去甲丙眯嗪存在的情况下，这种增加变得不明显（P〉0．05）。结论：离体鼠心脏急性冬眠时，不伴有心脏去甲肾上腺素自发性释放的明显增加。而酪胺可引起心率和去甲肾上腺素释放的明显增加．提示心脏交感神经末梢的能量并没有被耗竭；电场刺激引起的心脏去甲肾上腺素释放明显减少。复灌后这种释放恢复至对照组水平．提示在急性心肌冬眠过程中，心脏的交感神经功能可能也经历了一个类似冬眠即神经冬眠的过程。

Release of myocardial noradrenalin during acute hibernation

Objective： To investigate the release of myocardial noradrenalin during acute myocardial hibernation. Methods： A total of 36 male Sprague Dawley rats were randomly divided into 6 groups （n= 6rats/group） ： （1） control group, （2） hibernation group, （3） hibernation tyraminegroup, （4） reperfusion group, （5） reperfusion＋tyramine group, （6） reperfusin＋desipramine＋tyramine group. The hearts were extracted from rats and set up as acute hibernation models. The spontaneous and stimulation-evoked releases of myocardial noradrenalin during acute hibernation were determined by using a high-performance liquid chromatography （HPLC） method, the effect of desipramine and tyramine on release of myocardial noradrenalin was also evaluated. Results： The content of noradrenafin in coronary effluent at 1- min low-- flow, 120 - min low- flow and after addition of desipramine was respectively （ 1.9±0. 5）, （2.0±0.4） and （1.9±0.4） pmol/g ·min in hibernation group, there was no significant difference among them （P〉 0.05） ; The stimulation-evoked myocardial noradrenalin release was respectively （76.9 ± 27.7 ）, （3.3 ± 1.3） and （80. 3±23.9） pmol/g · min in control group, hibernation group and reperfusion group, compared to control group or reperfusion group, the release of nordrenalin was significant decreased （P〈0. 05） in hibernation group, noradrenalin content and heart rate significant increased in hibernation＋tyramine group and reperfusin＋tyramine group, but the increased was no significant in the presence of desipramine （reperfusin＋desipramine＋tyramine group）. Conclusion： These studies indicated that there is no significant increase in noradrenalin overflow and tyramine increase noradrenalin content during acute myocardial hibernation in isolated rat hearts, suggesting that the energy of myocardial sympathetic nerve terminal may not be depleted; The stimulation-evoked noradrenalin release significantly decreased during acute hibernation and restored to the level of control group after reperfusion, suggesting that the function of myocardial sympathetic nerve may also have a hibernation as myocardium does during acute myocardial hibernation.