Neurons in sensory ganglia are wrapped completely by satellite glial cells (SGCs). One putative function of SGCs is to regulate the neuronal microenvironment, but this role has received only little attention. In this study we investigated whether the SGC envelope serves a barrier function and how SGCs may control the neuronal microenvironment. We studied this question on short-term (<24 h) cell cultures of dorsal root ganglia and trigeminal ganglia from adult mice, which contain neurons surrounded with SGCs, and neurons that are not. Using calcium imaging, we measured neuronal responses to molecules with established actions on sensory neurons. We found that neurons surrounded by SGCs had a smaller response to molecules such as adenosine triphosphate (ATP), glutamate, GABA, and bradykinin than neurons without glial cover. When we inhibited the activity of NTPDases, which hydrolyze the ATP, and also when we inhibited the glutamate and GABA transporters on SGCs, this difference in the neuronal response was no longer observed. We conclude that the SGC envelope does not hinder diffusional passage, but acts as a metabolic barrier that regulates the neuronal microenvironment, and can protect the neurons and modulate their activity.

中文翻译：

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感觉神经节卫星胶质细胞的保护屏障作用

感觉神经节中的神经元完全被卫星胶质细胞（SGC）包裹。 SGC 的一个假定功能是调节神经元微环境，但这一作用很少受到关注。在这项研究中，我们研究了 SGC 包膜是否具有屏障功能以及 SGC 如何控制神经元微环境。我们对成年小鼠的背根神经节和三叉神经节的短期（<24 小时）细胞培养物进行了研究，其中包含被 SGC 包围的神经元和未被 SGC 包围的神经元。使用钙成像，我们测量了神经元对对感觉神经元具有既定作用的分子的反应。我们发现，与没有神经胶质覆盖的神经元相比，被 SGC 包围的神经元对三磷酸腺苷 (ATP)、谷氨酸、GABA 和缓激肽等分子的反应较小。当我们抑制 NTPDase 的活性（水解 ATP）以及抑制 SGC 上的谷氨酸和 GABA 转运蛋白时，不再观察到神经元反应的这种差异。我们得出的结论是，SGC 包膜不会阻碍扩散通道，而是作为调节神经元微环境的代谢屏障，可以保护神经元并调节其活动。