Inhibitory and excitatory axon terminals share a common nano-architecture of their Cav2.1 (P/Q-type) Ca(2+) channels.
Inhibitory and excitatory axon terminals share a common nano-architecture of their Cav2.1 (P/Q-type) Ca(2+) channels.
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DOI：
10.3389/fncel.2015.00315
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发表时间：
2015
影响因子：
5.3
通讯作者：
Kulik Á
中科院分区：
文献类型：
--
作者：
Althof D;Baehrens D;Watanabe M;Suzuki N;Fakler B;Kulik Á
调节抑制性和兴奋性神经递质释放的时程和强度是皮质网络活动精确操作的基础，并且由通过高电压激活的P/Q型Ca 2+（Cav2.1）通道进入突触前末梢的Ca 2+内流控制。正确的通道介导的Ca 2+信号传导关键取决于突触前膜中通道的拓扑结构。在这里，我们使用高分辨率SDS消化的冷冻断裂复制免疫电子显微镜连同Cav2.1免疫金标记的自动化计算分析，以确定Cav2.1通道在抑制性和兴奋性终端的精确亚细胞组织。标记Cav2.1通道的成孔α1亚基的免疫颗粒在突触膜的活性区上富集，通道的数量（3-62）与突触膜的面积相关。详细的分析表明，Cav2.1通道在突触前膜特化上不均匀分布，其中它们以每簇平均五个通道的簇排列，覆盖直径约为70 nm的平均面积。重要的是，簇状排列和簇状性质在GABA能和谷氨酸能终末之间没有显示出任何显著差异。我们的数据表明，在海马CA 1区的放射层中的抑制性和兴奋性终扣中Cav2.1通道具有共同的纳米结构，这表明簇排列对于从轴突终扣精确释放递质至关重要。
Tuning of the time course and strength of inhibitory and excitatory neurotransmitter release is fundamental for the precise operation of cortical network activity and is controlled by Ca2+ influx into presynaptic terminals through the high voltage-activated P/Q-type Ca2+ (Cav2.1) channels. Proper channel-mediated Ca2+-signaling critically depends on the topographical arrangement of the channels in the presynaptic membrane. Here, we used high-resolution SDS-digested freeze-fracture replica immunoelectron microscopy together with automatized computational analysis of Cav2.1 immunogold labeling to determine the precise subcellular organization of Cav2.1 channels in both inhibitory and excitatory terminals. Immunoparticles labeling the pore-forming α1 subunit of Cav2.1 channels were enriched over the active zone of the boutons with the number of channels (3–62) correlated with the area of the synaptic membrane. Detailed analysis showed that Cav2.1 channels are non-uniformly distributed over the presynaptic membrane specialization where they are arranged in clusters of an average five channels per cluster covering a mean area with a diameter of about 70 nm. Importantly, clustered arrangement and cluster properties did not show any significant difference between GABAergic and glutamatergic terminals. Our data demonstrate a common nano-architecture of Cav2.1 channels in inhibitory and excitatory boutons in stratum radiatum of the hippocampal CA1 area suggesting that the cluster arrangement is crucial for the precise release of transmitters from the axonal boutons.