Abt. Neuro- und Sinnesphysiologie, Zentrum Physiologie und Pathophysiologie, Georg-August-Universität, Göttingen, Germany.
PLoS One. 2011;6(10):e26309. doi: 10.1371/journal.pone.0026309. Epub 2011 Oct 19.
Respiratory neuronal network activity is thought to require efficient functioning of astrocytes. Here, we analyzed neuron-astrocyte communication in the pre-Bötzinger Complex (preBötC) of rhythmic slice preparations from neonatal mice. In astrocytes that exhibited rhythmic potassium fluxes and glutamate transporter currents, we did not find a translation of respiratory neuronal activity into phase-locked astroglial calcium signals. In up to 20% of astrocytes, 2-photon calcium imaging revealed spontaneous calcium fluctuations, although with no correlation to neuronal activity. Calcium signals could be elicited in preBötC astrocytes by metabotropic glutamate receptor activation or after inhibition of glial glutamate uptake. In the latter case, astrocyte calcium elevation preceded a surge of respiratory neuron discharge activity followed by network failure. We conclude that astrocytes do not exhibit respiratory-rhythmic calcium fluctuations when they are able to prevent synaptic glutamate accumulation. Calcium signaling is, however, observed when glutamate transport processes in astrocytes are suppressed or neuronal discharge activity is excessive.
呼吸神经元网络的活动被认为需要星形胶质细胞的有效功能。在这里，我们分析了来自新生小鼠节律性切片制剂的 Pre-Bötzinger 复合体（preBötC）中的神经元-星形胶质细胞通讯。在表现出节律性钾通量和谷氨酸转运体电流的星形胶质细胞中，我们没有发现呼吸神经元活动转化为与相位锁定的星形胶质细胞钙信号。在多达 20%的星形胶质细胞中，双光子钙成像显示自发钙波动，尽管与神经元活动没有相关性。代谢型谷氨酸受体激活或抑制神经胶质谷氨酸摄取后，可以在 Pre-BötC 星形胶质细胞中引发钙信号。在后一种情况下，星形胶质细胞钙升高先于呼吸神经元放电活动的激增，随后是网络衰竭。我们的结论是，当星形胶质细胞能够防止突触谷氨酸积累时，它们不会表现出呼吸节律性钙波动。然而，当星形胶质细胞中的谷氨酸转运过程受到抑制或神经元放电活动过度时，会观察到钙信号。
