Spatial and temporal activation of brain regions in hibernation: c-fos expression during the hibernation bout in thirteen-lined ground squirrel

András Bratincsák, David McMullen, Shinichi Miyake, Zsuzsanna E. Tóth, John M. Hallenbeck, Miklós Palkovits

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Hibernation results in dramatic changes in body temperature and metabolism; however, the central nervous system remains active during deep torpor. By cloning c-fos cDNA from the 13-lined ground squirrel (Spermophilus tridecemlineatus) and using squirrel c-fos mRNA probe for in situ hybridization histochemistry, we systematically analyzed and identified specific brain regions that were activated during six different phases of the hibernation bout. During entrance into torpor, we detected activation of the ventrolateral subdivision of the medial preoptic area ('thermoregulatory center'), and the reticular thalamic nucleus, which is known to inhibit the somatomotor cortex. During torpor, c-fos expression in the cortex was suppressed while the reticular thalamic nucleus remained uniformly active. Throughout torpor the suprachiasmatic nucleus ('biological clock') showed increasing activity, likely participating in phase-change regulation of the hibernation bout. Interestingly, during torpor very strong c-fos activation was seen in the epithelial cells of the choroid plexus and in tanycytes at the third ventricle, both peaking near the beginning of arousal. In arousal, activity of the suprachiasmatic and reticular thalamic nuclei and choroid epithelial cells diminished, while ependymal cells in the lateral and fourth ventricles showed stronger activity. Increasing body temperature during arousal was driven by the activation of neurons in the medial part of the preoptic area. In interbout awake animals, we demonstrated the activation of hypothalamic neurons located in the arcuate nucleus and the dorsolateral hypothalamus, areas involved in food intake. Our observations indicate that the hibernation bout is closely regulated and orchestrated by specific regions of the central nervous system.

Original languageEnglish
Pages (from-to)443-458
Number of pages16
JournalJournal of Comparative Neurology
Volume505
Issue number4
DOIs
Publication statusPublished - Dec 1 2007

Keywords

  • Choroid plexus
  • Ependyma
  • Hibernation bout
  • Preoptic nucleus
  • Tanycytes
  • Thermoregulation
  • c-fos

ASJC Scopus subject areas

  • Neuroscience(all)

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