Glycinergic transmission and postsynaptic activation of CaMKII are required for glycine receptor clustering in vivo
Glycinergic transmission and postsynaptic activation of CaMKII are required for glycine receptor clustering in vivo
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DOI：
10.1111/gtc.12032
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发表时间：
2013-03
期刊：
影响因子：
2.1
通讯作者：
Iori Yamanaka;Mariko Miki;K. Asakawa;K. Kawakami;Y. Oda;Hiromi Hirata
中科院分区：
文献类型：
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作者：
Iori Yamanaka;Mariko Miki;K. Asakawa;K. Kawakami;Y. Oda;Hiromi Hirata
突触后部位神经递质受体积累的突触传递依赖性调节是突触功能形成、维持和成熟的基础。先前的体外研究表明，甘氨酸受体（GlyR）的聚集需要突触输入。然而，在体内GlyR调节突触传递尚未完全理解。在这里，我们使用发育中的斑马鱼建立了一个模型系统，其中GlyR在Mauthner细胞（M-细胞）中表达，Mauthner细胞是一对巨大的网状脊髓后脑神经元，从而能够在可识别的细胞中分析GlyR簇随时间的变化。将甘氨酸能阻断剂士的宁应用于发育中的斑马鱼，阻止了M细胞中突触后GlyR簇的形成。士的宁去除后，GlyR簇出现在M细胞中。在后期阶段，甘氨酸能传递阻断损害GlyR簇的维持。我们还发现，药理学阻断L-型Ca 2+通道或钙/钙调蛋白依赖性蛋白激酶II（CaMKII）会干扰GlyR的聚集。此外，使用Gal 4-UAS系统的M细胞特异性CaMKII失活显著损害了M细胞中的GlyR聚集。因此，在发育中的动物中，M细胞中GlyR簇的形成和维持以突触传递依赖的方式进行调节，并且突触后的CaMKII激活对于GlyR簇是必不可少的。这是第一次证明突触GlyR在体内的突触传递依赖性调节。
Synaptic transmission‐dependent regulation of neurotransmitter receptor accumulation at postsynaptic sites underlies the formation, maintenance and maturation of synaptic function. Previous in vitro studies showed that glycine receptor (GlyR) clustering requires synaptic inputs. However, in vivo GlyR regulation by synaptic transmission is not fully understood. Here, we established a model system using developing zebrafish, in which GlyRs are expressed in Mauthner cells (M‐cells), a pair of giant, reticulospinal, hindbrain neurons, thereby enabling analysis of GlyR clusters over time in identifiable cells. Bath application of a glycinergic blocker, strychnine, to developing zebrafish prevented postsynaptic GlyR cluster formation in the M‐cells. After strychnine removal, the GlyR clusters appeared in the M‐cells. At a later stage, glycinergic transmission blockade impaired maintenance of GlyR clusters. We also found that pharmacological blockade of either L‐type Ca2+ channels or calcium‐/calmodulin‐dependent protein kinase II (CaMKII) disturbed GlyR clustering. In addition, the M‐cell‐specific CaMKII inactivation using the Gal4‐UAS system significantly impaired GlyR clustering in the M‐cells. Thus, the formation and maintenance of GlyR clusters in the M‐cells in the developing animals are regulated in a synaptic transmission‐dependent manner, and CaMKII activation at the postsynapse is essential for GlyR clustering. This is the first demonstration of synaptic transmission‐dependent modulation of synaptic GlyRs in vivo.