Fischer Timo, Prey Jessica, Eschholz Lena, Rotermund Natalie, Lohr Christian
Division of Neurophysiology, Department of Biology, Institute of Zoology, University of Hamburg, Hamburg, Germany.
Front Cell Neurosci. 2021 Mar 23;15:639754. doi: 10.3389/fncel.2021.639754. eCollection 2021.
It is well-established that astrocytes respond to norepinephrine with cytosolic calcium rises in various brain areas, such as hippocampus or neocortex. However, less is known about the effect of norepinephrine on olfactory bulb astrocytes. In the present study, we used confocal calcium imaging and immunohistochemistry in mouse brain slices of the olfactory bulb, a brain region with a dense innervation of noradrenergic fibers, to investigate the calcium signaling evoked by norepinephrine in astrocytes. Our results show that application of norepinephrine leads to a cytosolic calcium rise in astrocytes which is independent of neuronal activity and mainly mediated by PLC/IP3-dependent internal calcium release. In addition, store-operated calcium entry (SOCE) contributes to the late phase of the response. Antagonists of both α1- and α2-adrenergic receptors, but not β-receptors, largely reduce the adrenergic calcium response, indicating that both α-receptor subtypes mediate norepinephrine-induced calcium transients in olfactory bulb astrocytes, whereas β-receptors do not contribute to the calcium transients.
众所周知，在海马体或新皮质等不同脑区，星形胶质细胞会对去甲肾上腺素产生反应，导致胞质钙升高。然而，关于去甲肾上腺素对嗅球星形胶质细胞的影响，人们了解较少。在本研究中，我们在嗅球的小鼠脑片中使用共聚焦钙成像和免疫组织化学方法，该脑区有密集的去甲肾上腺素能纤维支配，以研究去甲肾上腺素在星形胶质细胞中引发的钙信号。我们的结果表明，应用去甲肾上腺素会导致星形胶质细胞胞质钙升高，这与神经元活动无关，主要由PLC/IP3依赖性的细胞内钙释放介导。此外，储存式钙内流（SOCE）有助于反应的后期阶段。α1和α2肾上腺素能受体的拮抗剂，但不是β受体的拮抗剂，在很大程度上降低了肾上腺素能钙反应，表明这两种α受体亚型均介导去甲肾上腺素诱导的嗅球星形胶质细胞钙瞬变，而β受体对钙瞬变没有贡献。
