Activation-Dependent Rapid Postsynaptic Clustering of Glycine Receptors in Mature Spinal Cord Neurons.
Activation-Dependent Rapid Postsynaptic Clustering of Glycine Receptors in Mature Spinal Cord Neurons.
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DOI：
10.1523/eneuro.0194-16.2017
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发表时间：
2017-01
期刊：
影响因子：
3.4
通讯作者：
Nabekura J
中科院分区：
文献类型：
--
作者：
Nakahata Y;Eto K;Murakoshi H;Watanabe M;Kuriu T;Hirata H;Moorhouse AJ;Ishibashi H;Nabekura J
抑制性突触在发育过程中建立，但在成熟的神经系统中继续产生和调节强度。在脊髓和脑干中，突触前释放的抑制性神经递质在体内正常发育期间主要从GABA转换为甘氨酸。虽然抑制性神经传递的转变的突触前机制被很好地研究，但突触后神经递质受体对这种转变的贡献还没有完全阐明。甘氨酸受体（GlyRs）的突触簇在早期发育中受到激活依赖性去极化的调节。然而，GlyR激活诱导超极化后的第一个出生后的一周，很少有人知道是否以及如何突触前释放的甘氨酸调节突触后受体的去极化独立的方式在成熟的发育阶段。在这里，我们开发的啮齿动物脊髓神经元培养使用慢性士的宁应用，以调查是否初始激活的GlyRs在成熟阶段可以改变突触后定位的GlyRs。免疫细胞化学分析表明，慢性阻断GlyR激活，直到成熟的发育阶段导致突触后GlyR，可以扩大受体激活1小时后，在成熟阶段的较小的集群。此外，活细胞成像技术表明，GlyR激活减少其在突触的侧向扩散，这种现象是依赖于PKC，但既不Ca 2+也不CaMK II活性。这些结果表明，成熟期GlyR的激活可以调节抑制性突触上受体的扩散和簇的大小，这不仅为研究抑制性神经传递的突触后机制提供了新的视角，而且为研究成熟期抑制性突触的可塑性提供了新的思路。
Inhibitory synapses are established during development but continue to be generated and modulated in strength in the mature nervous system. In the spinal cord and brainstem, presynaptically released inhibitory neurotransmitter dominantly switches from GABA to glycine during normal development in vivo. While presynaptic mechanisms of the shift of inhibitory neurotransmission are well investigated, the contribution of postsynaptic neurotransmitter receptors to this shift is not fully elucidated. Synaptic clustering of glycine receptors (GlyRs) is regulated by activation-dependent depolarization in early development. However, GlyR activation induces hyperpolarization after the first postnatal week, and little is known whether and how presynaptically released glycine regulates postsynaptic receptors in a depolarization-independent manner in mature developmental stage. Here we developed spinal cord neuronal culture of rodents using chronic strychnine application to investigate whether initial activation of GlyRs in mature stage could change postsynaptic localization of GlyRs. Immunocytochemical analyses demonstrate that chronic blockade of GlyR activation until mature developmental stage resulted in smaller clusters of postsynaptic GlyRs that could be enlarged upon receptor activation for 1 h in the mature stage. Furthermore, live cell-imaging techniques show that GlyR activation decreases its lateral diffusion at synapses, and this phenomenon is dependent on PKC, but neither Ca2+ nor CaMKII activity. These results suggest that the GlyR activation can regulate receptor diffusion and cluster size at inhibitory synapses in mature stage, providing not only new insights into the postsynaptic mechanism of shifting inhibitory neurotransmission but also the inhibitory synaptic plasticity in mature nervous system.