Clayton E C, Williams C L
Department of Psychology, University of Virginia, 102 Gilmer Hall, PO Box 400400, Charlottesville, VA 22904-4400, USA.
Behav Brain Res. 2000 Jul;112(1-2):151-8. doi: 10.1016/s0166-4328(00)00178-9.
It is well documented that noradrenergic systems in the amygdala modulate memory formation, however, less research has examined how sources of limbic norepinephrine contribute to this process. The amygdala receives a dense supply of norepinephrine from neurons in the nucleus of the solitary tract (NTS). The present experiments examined whether adrenergic activation of these NTS neurons affects memory in learning tasks that are sensitive to amygdala norepinephrine release. Separate groups of male Sprague-Dawley rats were trained in either an emotionally arousing or spatial memory task. They then received vehicle or the adrenergic agonist epinephrine (50, 125, or 250 ng/0.5 microl) into the NTS. Rats given the 125 ng dose had significantly longer retention latencies on a 48 h inhibitory avoidance retention test and made a significantly higher percentage of correct responses on an 18 h delayed radial maze retention test. A third experiment using in vivo microdialysis and high performance liquid chromatography (HPLC) demonstrated that intra-NTS infusion of a memory-enhancing dose of epinephrine potentiated amygdala norepinephrine release. Collectively, these results suggest that stimulation of the NTS contributes to memory processing by influencing noradrenergic systems in the amygdala.
杏仁核中的去甲肾上腺素能系统调节记忆形成，这一点已有充分记录，然而，较少有研究探讨边缘系统去甲肾上腺素的来源如何促成这一过程。杏仁核从孤束核（NTS）的神经元接收密集的去甲肾上腺素供应。本实验研究了这些NTS神经元的肾上腺素能激活是否会影响对杏仁核去甲肾上腺素释放敏感的学习任务中的记忆。将雄性斯普拉格-道利大鼠分成不同组，分别训练其进行情绪唤起或空间记忆任务。然后，给它们向NTS内注射溶剂或肾上腺素能激动剂肾上腺素（50、125或250纳克/0.5微升）。接受125纳克剂量的大鼠在48小时抑制性回避记忆测试中的记忆潜伏期显著延长，在18小时延迟放射状迷宫记忆测试中的正确反应百分比显著提高。第三个使用体内微透析和高效液相色谱（HPLC）的实验表明，向NTS内注入增强记忆剂量的肾上腺素可增强杏仁核去甲肾上腺素的释放。总体而言，这些结果表明，刺激NTS通过影响杏仁核中的去甲肾上腺素能系统有助于记忆处理。
