title: Differences in activity of cytochrome C oxidase in brain between sleep and wakefulness.
abstract: OBJECTIVE
  Increased mRNA level of subunit 1 cytochrome c oxidase (COXI) during wakefulness and after short-term sleep deprivation has been described in brain. We hypothesized that this might contribute to increased activity of cytochrome oxidase (COX) enzyme during wakefulness, as part of the mechanisms to provide sufficient amounts of adenosine triphosphate to meet increased neuronal energy demands.
  
  
  METHODS
  COX activity was measured in isolated mitochondria from different brain regions in groups of rats with 3 hours of spontaneous sleep, 3 hours of spontaneous wake, and 3 hours of sleep deprivation. The group with 3 hours of spontaneous wake was added to delineate the circadian component of changes in the enzyme activity. Northern blot analysis was performed to examine the mRNA levels of 2 subunits of the enzyme COXI and COXIV, encoded by mitochondrial and nuclear DNA, respectively.
  
  
  METHODS
  Laboratory of Biochemistry, Department of Animal Biology, and Center for Sleep and Respiratory Neurobiology, University of Pennsylvania.
  
  
  METHODS
  2-month-old male Fischer rats (N = 21) implanted for polygraphic recording.
  
  
  RESULTS
  For COX activity, there was a main effect by analysis of variance of experimental group (P < .0001) with significant increases in COX activity in wake and sleep-deprived groups as compared to the sleep group. A main effect of brain region was also significant (P < .001). There was no difference between brain regions in the degree of increase in enzyme activity in wakefulness. Both COXI and COXIV mRNA were increased with wakefulness as compared to sleep.
  
  
  CONCLUSIONS
  There is an increase in COX activity after both 3 hours of spontaneous wake and 3 hours of sleep deprivation as compared with 3 hours of spontaneous sleep in diverse brain regions, which could be, in part, explained by the increased levels of bigenomic transcripts of the enzyme. This likely contributes to increased adenosine triphosphate production during wakefulness.
  
  
  BACKGROUND
  ADP, adenosine diphosphate; ATP, adenosine triphosphate; COXI, cytochrome c oxidase subunit 1 mRNA; COX, cytochrome c oxidase (protein); CREB, cyclic AMP response element binding protein; DNA, deoxyribonucleic acid; EDTA, ethylenediaminetetraacetic acid; EEG, electroencephalography; EMG, electromyography; GABP, GA binding protein; HEPES, 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid; mRNA, messenger ribonucleic acid; NADH, nicotinamid adenine dinucleotide, reduced; NDII, NADH dehydrogenase subunit 2 mRNA; NRF, nuclear respiratory factor.
authors.affiliation: Center for Sleep and Respiratory Neurobiology, School of Medicine, Hospital of the Univesity of Pennsylvania, Philadelphia, PA 19104-4283, USA. elenan@mail.med.upenn.edu
authors.forename: Elena V
authors.initials: EV
authors.lastname: Nikonova
authors.forename: Camasamudram
authors.initials: C
authors.lastname: Vijayasarathy
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Jacqueline R
authors.initials: JR
authors.lastname: Cater
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Galante
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Ward
authors.forename: Narayan G
authors.initials: NG
authors.lastname: Avadhani
authors.forename: Allan I
authors.initials: AI
authors.lastname: Pack
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D001921:Brain / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004569:Electroencephalography; D004576:Electromyography; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008928:Mitochondria / Q000201:enzymology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D012890:Sleep / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D018076:DNA, Complementary; D012333:RNA, Messenger; D003576:Electron Transport Complex IV