Vergara V, Penna M
Res Commun Chem Pathol Pharmacol. 1984 Oct;46(1):93-102.
Isolated cat heart papillary muscle bathed at 37 degrees C, electrically driven at the rate of 30 per min, subjected to high voltage stimulation, or the addition of tyramine 1.7 microM, or high doses of acetylcholine (0.55mM) induced a positive inotropic effect revealed by an increase of peak tension developed (PTD). Papillary muscles obtained from cats after 7 to 8 days chronic bilateral cervical vagotomy showed a basic PTD (mg) similar to papillary muscles from non vagotomized control or sham operated cats. The inotropic effect of both tyramine and high voltage stimulation was absent in these animals as compared to controls or sham operated cats. Nevertheless, the inotropic effect of high acetylcholine concentration was still present and was of similar magnitude than in muscles of sham operated cats. The results suggest the existence of a neural cholinergic mechanism that is suppressed by chronic vagotomy which might be necessary for the synthesis, storage and/or release of adrenergic neurotransmitter in ventricular myocardium. It is suggested also, that suppression of general trophic function of vagus nerve might interfere with inotropic actions mediated by norepinephrine release.
将离体猫心脏乳头肌置于37摄氏度的环境中，以每分钟30次的频率进行电驱动，施加高压刺激，或添加1.7微摩尔的酪胺，或高剂量的乙酰胆碱（0.55毫摩尔），会诱发正性肌力作用，表现为舒张期峰值张力（PTD）增加。从接受7至8天慢性双侧颈迷走神经切断术的猫身上获取的乳头肌，其基础PTD（毫克）与未行迷走神经切断术的对照猫或假手术猫的乳头肌相似。与对照猫或假手术猫相比，这些动物对酪胺和高压刺激均无正性肌力作用。然而，高浓度乙酰胆碱的正性肌力作用仍然存在，且与假手术猫肌肉中的作用幅度相似。结果表明存在一种神经胆碱能机制，慢性迷走神经切断术可抑制该机制，而该机制可能是心室心肌中肾上腺素能神经递质合成、储存和/或释放所必需的。还表明，迷走神经总体营养功能的抑制可能会干扰由去甲肾上腺素释放介导的正性肌力作用。
