Neural mechanism of propofol anesthesia in severe depression: a positron emission tomographic study.
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.
Ogawa
Kenichi
K
National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan. k-ogawa@pd5.so-net.ne.jp
Uema
Takeshi
T
Motohashi
Nobutaka
N
Nishikawa
Masami
M
Takano
Harumasa
H
Hiroki
Masahiko
M
Imabayashi
Etsuko
E
Ohnishi
Takashi
T
Inoue
Tomio
T
Takayama
Yutaka
Y
Takeda
Masatoshi
M
Matsuda
Hiroshi
H
Andoh
Tomio
T
Yamada
Yoshitsugu
Y
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
D018686:Anesthetics, Intravenous; D015742:Propofol