Christie Jason M, Bark Christine, Hormuzdi Sheriar G, Helbig Ingo, Monyer Hannah, Westbrook Gary L
Vollum Institute, Portland, Oregon, USA.
Neuron. 2005 Jun 2;46(5):761-72. doi: 10.1016/j.neuron.2005.04.030.
Neuronal synchrony is important to network behavior in many brain regions. In the olfactory bulb, principal neurons (mitral cells) project apical dendrites to a common glomerulus where they receive a common input. Synchronized activity within a glomerulus depends on chemical transmission but mitral cells are also electrically coupled. We examined the role of connexin-mediated gap junctions in mitral cell coordinated activity. Electrical coupling as well as correlated spiking between mitral cells projecting to the same glomerulus was entirely absent in connexin36 (Cx36) knockout mice. Ultrastructural analysis of glomeruli confirmed that mitral-mitral cell gap junctions on distal apical dendrites contain Cx36. Coupled AMPA responses between mitral cell pairs were absent in the knockout, demonstrating that electrical coupling, not transmitter spillover, is responsible for synchronization. Our results indicate that Cx36-mediated gap junctions between mitral cells orchestrate rapid coordinated signaling via a novel form of electrochemical transmission.
神经元同步对于许多脑区的网络行为很重要。在嗅球中，主要神经元（ mitral细胞）将顶端树突投射到一个共同的肾小球，在那里它们接收共同的输入。肾小球内的同步活动取决于化学传递，但mitral细胞也通过电耦合连接。我们研究了连接蛋白介导的缝隙连接在mitral细胞协调活动中的作用。在连接蛋白36（Cx36）基因敲除小鼠中，投射到同一肾小球的mitral细胞之间的电耦合以及相关的尖峰完全不存在。肾小球的超微结构分析证实，远端顶端树突上的mitral - mitral细胞缝隙连接含有Cx36。基因敲除小鼠中mitral细胞对之间的耦合AMPA反应不存在，这表明是电耦合而非递质溢出负责同步。我们的结果表明，mitral细胞之间由Cx36介导的缝隙连接通过一种新型的电化学传递形式协调快速的协同信号传导。
