Facultad de Medicina, Centro de Fisiología Celular e Integrativa, Clínica Alemana Universidad del Desarrollo Santiago, Chile ; Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile.
Laboratorio de Fisiología Celular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Santiago, Chile.
Front Cell Neurosci. 2014 Jun 20;8:158. doi: 10.3389/fncel.2014.00158. eCollection 2014.
Satellite glial cells (SGCs) are the main glia in sensory ganglia. They surround neuronal bodies and form a cap that prevents the formation of chemical or electrical synapses between neighboring neurons. SGCs have been suggested to establish bidirectional paracrine communication with sensory neurons. However, the molecular mechanism involved in this cellular communication is unknown. In the central nervous system (CNS), astrocytes present connexin43 (Cx43) hemichannels and pannexin1 (Panx1) channels, and the opening of these channels allows the release of signal molecules, such as ATP and glutamate. We propose that these channels could play a role in glia-neuron communication in sensory ganglia. Therefore, we studied the expression and function of Cx43 and Panx1 in rat and mouse nodose-petrosal-jugular complexes (NPJcs) using confocal immunofluorescence, molecular and electrophysiological techniques. Cx43 and Panx1 were detected in SGCs and in sensory neurons, respectively. In the rat and mouse, the electrical activity of vagal nerve increased significantly after nodose neurons were exposed to a Ca(2+)/Mg(2+)-free solution, a condition that increases the open probability of Cx hemichannels. This response was partially mimicked by a cell-permeable peptide corresponding to the last 10 amino acids of Cx43 (TAT-Cx43CT). Enhanced neuronal activity was reduced by Cx hemichannel, Panx1 channel and P2X7 receptor blockers. Moreover, the role of Panx1 was confirmed in NPJc, because in those from Panx1 knockout mice showed a reduced increase of neuronal activity induced by Ca(2+)/Mg(2+)-free extracellular conditions. The data suggest that Cx hemichannels and Panx channels serve as paracrine communication pathways between SGCs and neurons by modulating the excitability of sensory neurons.
卫星胶质细胞(SGCs)是感觉神经节中的主要胶质细胞。它们围绕神经元体形成一个帽状结构,防止相邻神经元之间形成化学或电突触。SGCs 被认为与感觉神经元建立双向旁分泌通讯。然而,这种细胞通讯涉及的分子机制尚不清楚。在中枢神经系统(CNS)中,星形胶质细胞存在连接蛋白 43(Cx43)半通道和 Pannexin1(Panx1)通道,这些通道的开放允许信号分子如 ATP 和谷氨酸的释放。我们提出这些通道可能在感觉神经节中的神经胶质-神经元通讯中发挥作用。因此,我们使用共聚焦免疫荧光、分子和电生理技术研究了大鼠和小鼠结状神经节-岩神经节-颈静脉复合体(NPJcs)中 Cx43 和 Panx1 的表达和功能。Cx43 和 Panx1 分别在 SGCs 和感觉神经元中被检测到。在大鼠和小鼠中,当迷走神经节神经元暴露于无钙/镁溶液中时,迷走神经的电活动显著增加,这种条件增加了 Cx 半通道的开放概率。这种反应部分被对应 Cx43 最后 10 个氨基酸的细胞渗透性肽(TAT-Cx43CT)模拟。Cx 半通道、Panx1 通道和 P2X7 受体阻滞剂可减少增强的神经元活动。此外,Panx1 在 NPJc 中的作用得到了证实,因为在 Panx1 敲除小鼠的 NPJc 中,无钙/镁细胞外条件诱导的神经元活动增加减少。这些数据表明,Cx 半通道和 Panx 通道通过调节感觉神经元的兴奋性,作为 SGCs 和神经元之间的旁分泌通讯途径。