title: Neural mechanism of propofol anesthesia in severe depression: a positron emission tomographic study.
abstract: BACKGROUND
  The precise neural mechanisms of propofol anesthesia in humans are still unknown. The authors examined the acute effects of propofol on regional cerebral blood flow (rCBF) using positron emission tomography in patients with severe depression.
  
  
  METHODS
  In six severely depressed patients (mean age, 55.0 yr) scheduled for electroconvulsive therapy, anesthetic levels were monitored by electroencephalography, and rCBF was serially quantified in the awake, sedated, and anesthetized states. The authors used high-resolution positron emission tomography with 15O-labeled water and statistical parametric mapping 99 for imaging and analysis of the data.
  
  
  RESULTS
  Global cerebral blood flow showed sharp decreases from the awake level during the administration of propofol, decreasing 26.8% in the sedated state and 54.4% in the anesthetized state. Moreover, a dose effect was seen in both parietal cortices and the left lateral prefrontal region with larger regions of relative decrease in rCBF at higher propofol doses. At the higher dose, the values of rCBF in the pulvinar nucleus of the thalamus, the pontine tegmentum, and the cerebellar cortex were also affected. Meanwhile, there were few changes of relative rCBF in the basal frontal lobes during both sedated and anesthetized states.
  
  
  CONCLUSIONS
  As in earlier studies using normal subjects, pronounced suppression in rCBF in the brain stem reticular formation, the thalamus, and the parietal association cortex occurred even in severely depressed patients. However, previously reported decreases in rCBF in the basal frontal lobe were absent in depressed patients.
authors.affiliation: National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan. k-ogawa@pd5.so-net.ne.jp
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ogawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Uema
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Motohashi
authors.forename: Masami
authors.initials: M
authors.lastname: Nishikawa
authors.forename: Harumasa
authors.initials: H
authors.lastname: Takano
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hiroki
authors.forename: Etsuko
authors.initials: E
authors.lastname: Imabayashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohnishi
authors.forename: Tomio
authors.initials: T
authors.lastname: Inoue
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takayama
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Takeda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsuda
authors.forename: Tomio
authors.initials: T
authors.lastname: Andoh
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D000328:Adult; D000368:Aged; D000758:Anesthesia; D018686:Anesthetics, Intravenous / Q000493:pharmacokinetics / Q000494:pharmacology; D001783:Blood Flow Velocity / Q000187:drug effects; D001921:Brain / Q000000981:diagnostic imaging*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000187:drug effects; D016292:Procedural Sedation; D003866:Depressive Disorder / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D004565:Electroconvulsive Therapy; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015742:Propofol / Q000493:pharmacokinetics* / Q000494:pharmacology; D011859:Radiography; D014055:Tomography, Emission-Computed; D014851:Wakefulness
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol