Tsumoto T, Hagihara K, Sato H, Hata Y
Nature. 1987;327(6122):513-4. doi: 10.1038/327513a0.
Acidic amino acids, such as glutamate and aspartate, are thought to be excitatory transmitters in the cerebral neocortex and hippocampus. Receptors for these amino acids can be classified into at least three types on the basis of their agonists. Quisqualate-preferring receptors and kainate-preferring receptors are implicated in the mediation of synaptic transmission in many regions including the hippocampus and visual cortex, whereas N-methyl-D-aspartate (NMDA)-preferring receptors are thought to be involved in modulating synaptic efficacy, for example in longterm potentiation, a form of synaptic plasticity in the hippocampus. In the visual cortex of the cat and monkey, it is well established that synaptic plasticity, estimated by susceptibility of binocular responsiveness of cortical neurons to monocular visual deprivation, disappears after the 'critical' period of postnatal development. Here we report that during the critical period in young kittens, a selective NMDA-receptor antagonist blocks visual responses of cortical neurons much more effectively than it does in the adult cat. This suggests that NMDA receptors may be involved in establishing synaptic plasticity in the kitten visual cortex.
酸性氨基酸，如谷氨酸和天冬氨酸，被认为是大脑新皮层和海马体中的兴奋性递质。这些氨基酸的受体根据其激动剂可至少分为三种类型。偏爱quisqualate的受体和偏爱海人酸的受体参与包括海马体和视觉皮层在内的许多区域的突触传递介导，而偏爱N-甲基-D-天冬氨酸（NMDA）的受体则被认为参与调节突触效能，例如在长时程增强中，这是海马体中一种突触可塑性的形式。在猫和猴的视觉皮层中，众所周知，通过皮层神经元双眼反应性对单眼视觉剥夺的敏感性来估计的突触可塑性，在出生后发育的“关键”期之后消失。我们在此报告，在幼小猫的关键期内，一种选择性NMDA受体拮抗剂阻断皮层神经元视觉反应的效果比在成年猫中更有效。这表明NMDA受体可能参与小猫视觉皮层中突触可塑性的建立。
