Circadian rhythm generation and entrainment in astrocytes

Laura M. Prolo, Joseph S. Takahashi, Erik D. Herzog

Research output: Contribution to journalArticle

149 Scopus citations

Abstract

In mammals, the master circadian pacemaker is considered the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN consists of a heterogeneous population of neurons and relatively understudied glia. We investigated whether glia, like neurons, rhythmically express circadian genes. We generated pure cultures of cortical astrocytes from Period2::luciferase (Per2::luc) knock-in mice and Period1::luciferase (Per1::luc) transgenic rats and recorded bioluminescence as a real-time reporter of gene activity. We found that rat Per1::luc and mouse Per2::luc astroglia express circadian rhythms with a genetically determined period. These rhythms damped out after several days but were reinitiated by a variety of treatments, including a full volume exchange of the medium. If cultures were treated before damping out, the phase of Per1::luc rhythmicity was shifted, depending on the time of the pulse relative to the peak of Per1 expression. Glial rhythms entrained to daily 1.5°C temperature cycles and were significantly sustained when cocultured with explants of the adult SCN but not with cortical explants. Thus, multiple signals, including a diffusible factor(s) from the SCN, are sufficient to either entrain or restart circadian oscillations in cortical glia.

Original languageEnglish (US)
Pages (from-to)404-408
Number of pages5
JournalJournal of Neuroscience
Volume25
Issue number2
DOIs
StatePublished - Jan 12 2005

Keywords

  • Glia
  • Luciferase
  • Oscillator
  • Pacemaker
  • Period1 gene
  • Suprachiasmatic nucleus

ASJC Scopus subject areas

  • Neuroscience(all)

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