Sutor B, Hablitz J J
Department of Neurology, Baylor College of Medicine, Houston, TX 77030.
Neurosci Lett. 1989 Feb 13;97(1-2):111-7. doi: 10.1016/0304-3940(89)90148-1.
The present study examined the role of N-methyl-D-aspartic acid (NMDA) receptors in synaptic plasticity in regular-spiking cells of rat frontal cortex. Intracortical stimulation, at levels subthreshold for elicitation of action potentials, evoked a late excitatory postsynaptic potential (EPSP) in layer II-III neurons that was sensitive to the selective NMDA antagonist D-2-amino-5-phosphonovaleric acid (APV). This late EPSP showed marked short-term frequency-dependent depression, suggesting that it is polysynaptic in origin. Polysynaptic late EPSPs were selectively enhanced following high-frequency stimulation. This sustained increase in synaptic efficacy, or long-term potentiation, was expressed in regular spiking cells and appeared to result from activation of NMDA receptors on excitatory interneurons. These data demonstrate the existence of an NMDA-modulated polysynaptic circuit in the neocortex which displays several types of use-dependent plasticity.
本研究考察了N-甲基-D-天冬氨酸（NMDA）受体在大鼠额叶皮质规则放电细胞突触可塑性中的作用。皮层内刺激在低于引发动作电位阈值的水平下，诱发了II-III层神经元的晚期兴奋性突触后电位（EPSP），该电位对选择性NMDA拮抗剂D-2-氨基-5-磷酸戊酸（APV）敏感。这种晚期EPSP表现出明显的短期频率依赖性抑制，表明其起源于多突触。高频刺激后，多突触晚期EPSP被选择性增强。这种突触效能的持续增加，即长时程增强，在规则放电细胞中表现出来，并且似乎是由兴奋性中间神经元上的NMDA受体激活所致。这些数据证明了新皮层中存在一个由NMDA调节的多突触回路，该回路表现出几种类型的使用依赖性可塑性。
