Rapid stimulus-evoked astrocyte Ca2+ elevations and hemodynamic responses in mouse somatosensory cortex in vivo.
Increased neuron and astrocyte activity triggers increased brain blood flow, but controversy exists over whether stimulation-induced changes in astrocyte activity are rapid and widespread enough to contribute to brain blood flow control. Here, we provide evidence for stimulus-evoked Ca(2+) elevations with rapid onset and short duration in a large proportion of cortical astrocytes in the adult mouse somatosensory cortex. Our improved detection of the fast Ca(2+) signals is due to a signal-enhancing analysis of the Ca(2+) activity. The rapid stimulation-evoked Ca(2+) increases identified in astrocyte somas, processes, and end-feet preceded local vasodilatation. Fast Ca(2+) responses in both neurons and astrocytes correlated with synaptic activity, but only the astrocytic responses correlated with the hemodynamic shifts. These data establish that a large proportion of cortical astrocytes have brief Ca(2+) responses with a rapid onset in vivo, fast enough to initiate hemodynamic responses or influence synaptic activity.
Department of Neuroscience and Pharmacology and Center for Healthy Aging, University of Copenhagen, DK-2200 Copenhagen N, Denmark.
Barbara Lykke
BL
Lind
Alexey R
AR
Brazhe
Sanne Barsballe
SB
Jessen
Florence C C
FC
Tan
Martin J
MJ
Lauritzen
D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002450:Cell Communication / Q000502:physiology*; D005453:Fluorescence; D006439:Hemodynamics / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D017078:Laser-Doppler Flowmetry; D051379:Mice; D018613:Microscopy, Confocal; D013003:Somatosensory Cortex / Q000378:metabolism / Q000502:physiology*
D002118:Calcium
Ca2+ imaging; functional imaging; neurovascular coupling; sensory barrel cortex