Ca2+ Transients in Bergmann Glia during Locomotion Depend on Animal State of Arousal

Title: Ca2+ Transients in Bergmann Glia during Locomotion Depend on Animal State of Arousal

Journal: Neuron. 2014 Jun 18;82(6):1263-70.

Link: http://dx.doi.org/10.1016/j.neuron.2014.04.038

Comments:

Astrocytes are star-shaped glial cells in the brain and spinal cord, they perform many functions including neurotransmitter clearance, ion buffering. Astrocytes signal to neurons via releasing Ca2+, however, the role of Ca2+ signaling in astrocytes in vivo remains uncertain.

To explore the mechanisms that control astrocyte activity in vivo, the author developed transgenic knock-in mice (R26-lsl-GCaMP3), in which the encoded Ca2+ indicator GCaMP3 is able to be expressed in a cell-specific way. According to a previous study, we know the increase of Ca2+ within Bergmann glia has a connection with its brief bouts of locomotion, but the magnitude of the Bergmann glia Ca2+ response was not correlated with locomotion speed. Thus, they trained the GCaMP3-expressing mice to walk on a treadmill and monitored locomotion-induced Ca2+ levels in Bergmann glia. The result indicated that Bergmann glia often showed a widespread activity in the absence of locomotion. They also monitored muscle contraction during imaging trials, and it demonstrated that Ca2+ transients that occurred in the absence of locomotion were often associated with an increase in EMG power. Both studies raise the possibility that activity in Bergmann glia may correspond to increased arousal. .