NMDA receptor-mediated excitation and inhibition balance is required for somatosensory development and maturation

在本研究中，我们比较了GluN 2B和GluN 2D在桶发育中的功能作用。与对照组相比，GluN 2B +/-小鼠体感皮层中胡须相关图案的出现和关键期可塑性（CPP）的终止均延迟了近一天，但GluN 2D-/-小鼠提前了近一天。在两种小鼠的三叉神经通路的皮层下中继站也发现了类似的时间转移。相比之下，两种小鼠的桶皮质中的CPP的幅度是正常的。因此，GluN 2B和GluN 2D在桶的时间发育和成熟中起反作用，而不影响CPP的大小。在各中继站，谷氨酸能神经元突触中GluN 2B占优势，而GABA能神经元突触中GluN 2D则有选择性。总之，这些结果表明，谷氨酸能神经元中表达的GluN 2B促进体感发育，而GABA能神经元中表达的GluN 2D延迟体感发育。

In the present study, we compared functional roles of GluN2B and GluN2D in barrel development. Compared to control littermates, both the appearance of whisker-related patterning and the termination of critical period plasticity (CPP) were delayed by nearly a day in the somatosensory cortex of GluN2B+/- mice, but advanced by nearly a day in GluN2D-/- mice. Similar temporal shifts were also found at subcortical relay stations of the trigeminal pathway in both mice. By contrast, the magnitude of CPP in the barrel cortex was normal in both mice. Thus, GluN2B and GluN2D play counteractive roles in temporal development and maturation of barrels without affecting the magnitude of CPP. At each relay station, GluN2B was predominant at synapses of glutamatergic neurons while GluN2D was selective in GABAergic neurons. Taken together, these results indicate that GluN2B expressed in glutamatergic neurons facilitates somatosensory development, whereas GluN2D expressed in GABAergic neurons delays it.