Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
Excellence Cluster Multiscale Bioimaging (MBExC), Göttingen, Germany.
Life Sci Alliance. 2023 Oct 13;7(1). doi: 10.26508/lsa.202302030. Print 2024 Jan.
Calcium (Ca) is a well-known second messenger in all cells, and is especially relevant for neuronal activity. Neuronal Ca is found in different forms, with a minority being freely soluble in the cell and more than 99% being bound to proteins. Free Ca has received much attention over the last few decades, but protein-bound Ca has been difficult to analyze. Here, we introduce correlative fluorescence and nanoscale secondary ion mass spectrometry imaging as a tool to describe bound Ca As expected, bound Ca is ubiquitous. It does not correlate to free Ca dynamics at the whole-neuron level, but does correlate significantly to the intensity of markers for GABAergic pre-synapse and glutamatergic post-synapses. In contrast, a negative correlation to pre-synaptic activity was observed, with lower levels of bound Ca observed in the more active synapses. We conclude that bound Ca may regulate neuronal activity and should receive more attention in the future.
钙（Ca）是所有细胞中一种众所周知的第二信使，尤其与神经元活动相关。神经元中的 Ca 以不同的形式存在，其中少数是可自由溶解在细胞中的，超过 99%与蛋白质结合。在过去几十年中，自由 Ca 受到了广泛关注，但蛋白质结合的 Ca 一直难以分析。在这里，我们介绍相关的荧光和纳米级二次离子质谱成像作为一种工具来描述结合 Ca。如预期的那样，结合 Ca 无处不在。它与整个神经元水平的自由 Ca 动力学没有相关性，但与 GABA 能突触前和谷氨酸能突触后标记物的强度显著相关。相比之下，观察到与突触前活动呈负相关，在更活跃的突触中观察到结合 Ca 的水平较低。我们得出结论，结合 Ca 可能调节神经元活动，在未来应该受到更多关注。
