title: Loss of Sleep Affects the Ultrastructure of Pyramidal Neurons in the Adolescent Mouse Frontal Cortex.
abstract: OBJECTIVE
  The adolescent brain may be uniquely affected by acute sleep deprivation (ASD) and chronic sleep restriction (CSR), but direct evidence is lacking. We used electron microscopy to examine how ASD and CSR affect pyramidal neurons in the frontal cortex of adolescent mice, focusing on mitochondria, endosomes, and lysosomes that together perform most basic cellular functions, from nutrient intake to prevention of cellular stress.
  
  
  METHODS
  Adolescent (1-mo-old) mice slept (S) or were sleep deprived (ASD, with novel objects and running wheels) during the first 6-8 h of the light period, chronically sleep restricted (CSR) for > 4 days (using novel objects, running wheels, social interaction, forced locomotion, caffeinated water), or allowed to recover sleep (RS) for ∼32 h after CSR. Ultrastructural analysis of 350 pyramidal neurons was performed (S = 82; ASD = 86; CSR = 103; RS = 79; 4 to 5 mice/group).
  
  
  RESULTS
  Several ultrastructural parameters differed in S versus ASD, S versus CSR, CSR versus RS, and S versus RS, although the different methods used to enforce wake may have contributed to some of the differences between short and long sleep loss. Differences included larger cytoplasmic area occupied by mitochondria in CSR versus S, and higher number of secondary lysosomes in CSR versus S and RS. We also found that sleep loss may unmask interindividual differences not obvious during baseline sleep. Moreover, using a combination of 11 ultrastructural parameters, we could predict in up to 80% of cases whether sleep or wake occurred at the single cell level.
  
  
  CONCLUSIONS
  Ultrastructural analysis may be a powerful tool to identify which cellular organelles, and thus which cellular functions, are most affected by sleep and sleep loss.
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, Madison, WI.
authors.forename: Luisa
authors.initials: L
authors.lastname: de Vivo
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, Madison, WI.
authors.forename: Aaron B
authors.initials: AB
authors.lastname: Nelson
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, Madison, WI.
authors.forename: Michele
authors.initials: M
authors.lastname: Bellesi
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, Madison, WI.
authors.forename: Juliana
authors.initials: J
authors.lastname: Noguti
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, Madison, WI.
authors.forename: Giulio
authors.initials: G
authors.lastname: Tononi
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, Madison, WI.
authors.forename: Chiara
authors.initials: C
authors.lastname: Cirelli
mesh_terms: D000375:Aging; D000818:Animals; D005260:Female; D005625:Frontal Lobe / Q000473:pathology* / Q000648:ultrastructure; D008247:Lysosomes / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008928:Mitochondria / Q000473:pathology / Q000648:ultrastructure; D017966:Pyramidal Cells / Q000473:pathology* / Q000648:ultrastructure*; D012741:Sexual Maturation; D012890:Sleep / Q000502:physiology; D012892:Sleep Deprivation / Q000473:pathology* / Q000503:physiopathology*; D013997:Time Factors
keywords: chronic sleep restriction; electron microscopy; interindividual variability; lysosomes; mitochondria