Nitsche Michael A, Jaussi Wiebke, Liebetanz David, Lang Nicolas, Tergau Frithjof, Paulus Walter
Department Clinical Neurophysiology, Georg-August-University, Goettingen, Germany.
Neuropsychopharmacology. 2004 Aug;29(8):1573-8. doi: 10.1038/sj.npp.1300517.
D-Cycloserine (CYC), a partial N-methyl-D-aspartate (NMDA) agonist, has been shown to improve cognitive functions in humans. However, the neurophysiological basis of this effect is unclear so far. We studied the impact of this drug on long-lasting after-effects of transcranial direct current (tDCS)-generated motor cortical excitability shifts, as revealed by transcranial magnetic stimulation-elicited motor-evoked potentials. While anodal tDCS enhances motor cortical excitability, cathodal tDCS diminishes it. Both effects seem to be NMDA receptor dependent. D-CYC selectively potentiated the duration of motor cortical excitability enhancements induced by anodal tDCS. D-CYC alone did not modulate excitability. The potency of this drug to consolidate neuronal excitability enhancements, most probably by stabilizing the strengthening of NMDA receptors, which is a probable neurophysiological derivate of learning processes, makes it an interesting substance to improve cognitive functions.
D-环丝氨酸（CYC）是一种部分N-甲基-D-天冬氨酸（NMDA）激动剂，已被证明可改善人类的认知功能。然而，迄今为止，这种效应的神经生理学基础尚不清楚。我们研究了这种药物对经颅直流电（tDCS）产生的运动皮层兴奋性变化的长期后效应的影响，这是通过经颅磁刺激诱发的运动诱发电位来揭示的。阳极tDCS可增强运动皮层兴奋性，而阴极tDCS则会降低其兴奋性。这两种效应似乎都依赖于NMDA受体。D-CYC选择性地增强了阳极tDCS诱导的运动皮层兴奋性增强的持续时间。单独使用D-CYC不会调节兴奋性。这种药物巩固神经元兴奋性增强的能力，很可能是通过稳定NMDA受体的强化来实现的，而这可能是学习过程的一种神经生理学衍生物，使其成为一种改善认知功能的有趣物质。
