Astrocytic GABA production in circadian rhythm
Astrocytes can drive circadian behavior in mammals, but the nature of the temporal information generated by astrocytes is largely unknown.
The authors show that circadian phases of astrocytic activity are uniform across the suprachiasmatic nucleus (SCN), in contrast to the phase waves of neuronal activity.
Extracellular GABA levels in the SCN peak during the nighttime, mirroring the spatiotemporal organization of astrocytic rhythms, as opposed to the daytime peak of neuronal activity.
They also demonstrate that inhibition of synaptic GABA release desynchronizes neuronal circadian rhythms in the SCN, but does not affect extracellular GABA rhythms.
Inhibition of astrocytic GABA synthesis disrupts circadian rhythms of extracellular GABA and desynchronizes neuronal circadian activity, suggesting a role as an internal circadian synchronizer for the SCN circuit (“astrozeit”).
https://www.embopress.org/doi/full/10.1038/s44318-024-00324-w
