title: Resting-state brain glucose utilization as measured by PET is directly related to regional synaptophysin levels: a study in baboons.
abstract: It is classically recognized that regional cerebral glucose consumption (CMRglc), as measured by positron emission tomography (PET) and [18F]-2-fluorodeoxyglucose (FDG), is a precise index of the integrated local neuronal activity. However, despite extensive use of the FDG-PET method, the significance of the measured CMRglc has been little addressed so far. In the present study, we aimed for the first time to test whether resting-state CMRglc is directly related to synaptic density. To this end, we investigated in the baboon the relationships between CMR(glc) and the levels of synaptophysin (SY), a presynaptic protein classically used to assess synaptic density. CMR(glc), measured in vivo by FDG-PET at the resting-state, and SY levels, assessed postmortem by the Western blot technique, were quantified in seven brain areas of five baboons. By applying these two techniques to the same animals, we found significant positive correlations between CMR(glc) and SY levels, across all regions and all animals, as well as within individual baboons. These findings strongly support the hypothesis that resting-state CMR(glc) reflects integrated synaptic activity.
authors.affiliation: INSERM U320, Centre Cyceron, Caen, France.
authors.forename: Anne B
authors.initials: AB
authors.lastname: Rocher
authors.forename: Françoise
authors.initials: F
authors.lastname: Chapon
authors.forename: Xavier
authors.initials: X
authors.lastname: Blaizot
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Baron
authors.forename: Chantal
authors.initials: C
authors.lastname: Chavoix
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000000981:diagnostic imaging*; D001923:Brain Chemistry / Q000502:physiology*; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D008297:Male; D010215:Papio; D019275:Radiopharmaceuticals; D016708:Synaptophysin / Q000378:metabolism*; D014055:Tomography, Emission-Computed
chemical_list: D019275:Radiopharmaceuticals; D016708:Synaptophysin; D019788:Fluorodeoxyglucose F18; D005947:Glucose