College of Pharmacy, Rady Faculty of Health Sciences, University of Manitoba, 750 McDermot Avenue, Winnipeg, MG R3E 0T5, Canada.
Biomolecules. 2021 Oct 6;11(10):1467. doi: 10.3390/biom11101467.
Astrocytes are complex glial cells that play many essential roles in the brain, including the fine-tuning of synaptic activity and blood flow. These roles are linked to fluctuations in intracellular Ca within astrocytes. Recent advances in imaging techniques have identified localized Ca transients within the fine processes of the astrocytic structure, which we term microdomain Ca events. These Ca transients are very diverse and occur under different conditions, including in the presence or absence of surrounding circuit activity. This complexity suggests that different signalling mechanisms mediate microdomain events which may then encode specific astrocyte functions from the modulation of synapses up to brain circuits and behaviour. Several recent studies have shown that a subset of astrocyte microdomain Ca events occur rapidly following local neuronal circuit activity. In this review, we consider the physiological relevance of microdomain astrocyte Ca signalling within brain circuits and outline possible pathways of extracellular Ca influx through ionotropic receptors and other Ca ion channels, which may contribute to astrocyte microdomain events with potentially fast dynamics.
星形胶质细胞是复杂的神经胶质细胞，在大脑中发挥许多重要作用，包括微调突触活动和血流。这些作用与星形胶质细胞内细胞内 Ca 的波动有关。最近的成像技术进展已经确定了星形胶质细胞结构的精细过程中的局部 Ca 瞬变，我们称之为微域 Ca 事件。这些 Ca 瞬变非常多样化，并且在不同的条件下发生，包括在周围电路活动存在或不存在的情况下。这种复杂性表明，不同的信号机制介导微域事件，这些事件可能通过从突触调节到脑回路和行为的特定星形胶质细胞功能进行编码。最近的几项研究表明，在局部神经元回路活动后，星形胶质细胞微域 Ca 事件的一部分迅速发生。在这篇综述中，我们考虑了脑回路中微域星形胶质细胞 Ca 信号传递的生理相关性，并概述了通过离子型受体和其他 Ca 离子通道进行细胞外 Ca 内流的可能途径，这些途径可能有助于具有潜在快速动力学的星形胶质细胞微域事件。
