Cell reports
Astroglia regulate neurovascular coupling while engaging in signal exchange with neurons. The underlying cellular machinery is thought to rely on astrocytic Ca signals, but what controls their amplitude and waveform is poorly understood. Here, we employ time-resolved two-photon excitation fluorescence imaging in acute hippocampal slices and in cortex in vivo to find that resting [Ca] predicts the scale (amplitude) and the maximum (peak) of astroglial Ca elevations. We bidirectionally manipulate resting [Ca] by uncaging intracellular Ca or Ca buffers and use ratiometric imaging of a genetically encoded Ca indicator to establish that alterations in resting [Ca] change co-directionally the peak level and anti-directionally the amplitude of local Ca transients. This relationship holds for spontaneous and for induced (for instance by locomotion) Ca signals. Our findings uncover a basic generic rule of Ca signal formation in astrocytes, thus also associating the resting Ca level with the physiological "excitability" state of astroglia.
Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.
PMID: 32160550