title: The Role of the Suprachiasmatic Nucleus in Cardiac Autonomic Control during Sleep.
abstract: BACKGROUND
  The suprachiasmatic nucleus (SCN) may play an important role in central autonomic control, since its projections connect to (para)sympathetic relay stations in the brainstem and spinal cord. The cardiac autonomic modifications during nighttime may therefore not only result from direct effects of the sleep-related changes in the central autonomic network, but also from endogenous circadian factors as directed by the SCN. To explore the influence of the SCN on autonomic fluctuations during nighttime, we studied heart rate and its variability (HRV) in a clinical model of SCN damage.
  
  
  METHODS
  Fifteen patients in follow-up after surgical treatment for nonfunctioning pituitary macroadenoma (NFMA) compressing the optic chiasm (8 females, 26-65 years old) and fifteen age-matched healthy controls (5 females, 30-63 years) underwent overnight ambulatory polysomnography. Eleven patients had hypopituitarism and received adequate replacement therapy. HRV was calculated for each 30-second epoch and corrected for sleep stage, arousals, and gender using mixed effect regression models.
  
  
  RESULTS
  Compared to controls, patients spent more time awake after sleep onset and in NREM1-sleep, and less in REM-sleep. Heart rate, low (LF) and high frequency (HF) power components and the LF/HF ratio across sleep stages were not significantly different between groups.
  
  
  CONCLUSIONS
  These findings suggest that the SCN does not play a dominant role in cardiac autonomic control during sleep.
authors.affiliation: Department of Medicine, Division of Endocrinology, Centre for Endocrine Tumours Leiden, Leiden University Medical Centre, Leiden, Netherlands.
authors.forename: S D
authors.initials: SD
authors.lastname: Joustra
authors.affiliation: Department of Neurology, Leiden University Medical Centre, Leiden, Netherlands.
authors.forename: R H
authors.initials: RH
authors.lastname: Reijntjes
authors.affiliation: Department of Medicine, Division of Endocrinology, Centre for Endocrine Tumours Leiden, Leiden University Medical Centre, Leiden, Netherlands.
authors.forename: A M
authors.initials: AM
authors.lastname: Pereira
authors.affiliation: Department of Neurology, Leiden University Medical Centre, Leiden, Netherlands.|Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands.
authors.forename: G J
authors.initials: GJ
authors.lastname: Lammers
authors.affiliation: Department of Medicine, Division of Endocrinology, Centre for Endocrine Tumours Leiden, Leiden University Medical Centre, Leiden, Netherlands.
authors.forename: N R
authors.initials: NR
authors.lastname: Biermasz
authors.affiliation: Department of Neurology, Leiden University Medical Centre, Leiden, Netherlands.|Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands.
authors.forename: R D
authors.initials: RD
authors.lastname: Thijs
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000502:physiology*; D005260:Female; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012890:Sleep / Q000502:physiology*; D013493:Suprachiasmatic Nucleus / Q000502:physiology*