Work

Astrocytes Control Circadian Timekeeping in the Suprachiasmatic Nucleus via Glutamatergic Signaling

Year: 2017

Type: article

Abstract: The suprachiasmatic nucleus (SCN) of the hypothalamus orchestrates daily rhythms of physiology and behavior in mammals. Its circadian (∼24 hr) oscillations of gene expression and electrical activity are generated intrinsically and can persist indefinitely in temporal isolation. This robust and resilient timekeeping is generally regarded as a product of the intrinsic connectivity of its neurons. Here we show that neurons constitute only one "half" of the SCN clock, the one metabolically active during circadian daytime. In contrast, SCN astrocytes are active during circadian nighttime, when they suppress the activity of SCN neurons by regulating extracellular glutamate levels. This glutamatergic gliotransmission is sensed by neurons of the dorsal SCN via specific pre-synaptic NMDA receptor assemblies containing NR2C subunits. Remarkably, somatic genetic re-programming of intracellular clocks in SCN astrocytes was capable of remodeling circadian behavioral rhythms in adult mice. Thus, SCN circuit-level timekeeping arises from interdependent and mutually supportive astrocytic-neuronal signaling.

Source: Neuron

DOI: 10.1016/j.neuron.2017.02.030

Authors: Marco Brancaccio, Andrew P. Patton, Johanna E. Chesham, Elizabeth S. Maywood, Michael H. Hastings

Institutions: MRC Laboratory of Molecular Biology, University of Cambridge

Language: English

Topic: Circadian rhythm and melatonin

Subfield: Endocrine and Autonomic Systems

Field: Neuroscience

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $10,400

Funders: Wellcome Trust, Medical Research Council