Imaging the effects of propofol on human cerebral glucose metabolism using positron emission tomography

The effects of propofol on glucose metabolism in different cerebral regions were observed, using positron emission tomography (PET) technology, to determine a possible cerebral target region. Seven healthy volunteers were injected with (18)F-fluorodeoxyglucose developing agent for PET scanning whilst awake (control group T1), during sedation (induced by 1.5 microg/ml propofol administered by target controlled injection [TCI], group T2) and when unconsciousness (induced by 2.5 microg/ml propofol administered by TCI, group T3). Whole brain glucose metabolism was reduced during propofol anaesthesia; this was initially observed in the cortical areas at the lower dose of propofol (group T2) but extended to the subcortical regions, especially the thalamus and hippocampus, at the higher dose (group T3). This suggests that these regions of the brain might be important targets that are susceptible to propofol.