title: The action sites of propofol in the normal human brain revealed by functional magnetic resonance imaging.
abstract: Propofol has been used for many years but its functional target in the intact brain remains unclear. In the present study, we used functional magnetic resonance imaging to demonstrate blood oxygen level dependence signal changes in the normal human brain during propofol anesthesia and explored the possible action targets of propofol. Ten healthy subjects were enrolled in two experimental sessions. In session 1, the Observer's Assessment of Alertness/Sedation Scale was performed to evaluate asleep to awake/alert status. In session 2, images with blood oxygen level dependence contrast were obtained with echo-planar imaging on a 1.5-T Philips Gyroscan Magnetic Resonance System and analyzed. In both sessions, subjects were intravenously administered with saline (for 3 min) and then propofol (for 1.5 min) and saline again (for 10.5 min) with a constant speed infusion pump. Observer's Assessment of Alertness/Sedation Scale scoring showed that the subjects experienced conscious–sedative–unconscious–analepsia, which correlated well with the signal decreases in the anesthesia states. Propofol induced significant signal decreases in hypothalamus (18.2%±3.6%), frontal lobe (68.5%±11.2%), and temporal lobe (34.7%±6.1%). Additionally, the signals at these three sites were fulminant and changed synchronously. While in the thalamus, the signal decrease was observed in 5 of 10 of the subjects and the magnitude of decrease was 3.9%±1.6%. These results suggest that there is most significant inhibition in hypothalamus, frontal lobe, and temporal in propofol anesthesia and moderate inhibition in thalamus. These brain regions might be the targets of propofol anesthesia in human brain.
authors.affiliation: Department of Anesthesiology, School of Stomatology, Fourth Military Medical University, and Xijing Hospital, Xi'an, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Zhijing
authors.initials: Z
authors.lastname: Zhao
authors.forename: Yali
authors.initials: Y
authors.lastname: Ge
authors.forename: Jinsong
authors.initials: J
authors.lastname: Zhang
authors.forename: Daihua
authors.initials: D
authors.lastname: Yu
authors.forename: Wei
authors.initials: W
authors.lastname: Chai
authors.forename: Shengxi
authors.initials: S
authors.lastname: Wu
authors.forename: Lixian
authors.initials: L
authors.lastname: Xu
mesh_terms: D000328:Adult; D000758:Anesthesia; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D001921:Brain / Q000033:anatomy & histology / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology; D001931:Brain Mapping / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology; D003243:Consciousness / Q000187:drug effects* / Q000502:physiology; D005625:Frontal Lobe / Q000033:anatomy & histology / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006993:Hypnotics and Sedatives / Q000493:pharmacokinetics*; D007031:Hypothalamus / Q000033:anatomy & histology / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010100:Oxygen / Q000097:blood; D015742:Propofol / Q000493:pharmacokinetics* / Q000494:pharmacology*; D012016:Reference Values; D013702:Temporal Lobe / Q000033:anatomy & histology / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism; D013788:Thalamus / Q000033:anatomy & histology / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism
chemical_list: D018686:Anesthetics, Intravenous; D006993:Hypnotics and Sedatives; D010100:Oxygen; D015742:Propofol