title: Brain incorporation of [1-11C]arachidonate in normocapnic and hypercapnic monkeys, measured with positron emission tomography.
abstract: Positron emission tomography (PET) was used to determine brain incorporation coefficients k* of [1-11C]arachidonate in isoflurane-anesthetized rhesus monkeys, as well as cerebral blood flow (CBF) using [15O]water. Intravenously injected [1-11C]arachidonate disappeared from plasma with a half-life of 1.1 min, whereas brain radioactivity reached a steady-state by 10 min. Mean values of k* were the same whether calculated by a single-time point method at 20 min after injection began, or by least-squares fitting of an equation for total brain radioactivity to data at all time points. k* equalled 1.1-1.2 x 10(-4) ml x s(-1) x g(-1) in gray matter and was unaffected by a 2.6-fold increase in CBF caused by hypercapnia. These results indicate that brain incorporation of [1-11C]arachidonate can be quantified in the primate using PET, and that incorporation is flow-independent.
authors.affiliation: Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Chang
authors.forename: T
authors.initials: T
authors.lastname: Arai
authors.forename: L M
authors.initials: LM
authors.lastname: Freed
authors.forename: S
authors.initials: S
authors.lastname: Wakabayashi
authors.forename: M A
authors.initials: MA
authors.lastname: Channing
authors.forename: B B
authors.initials: BB
authors.lastname: Dunn
authors.forename: M G
authors.initials: MG
authors.lastname: Der
authors.forename: J M
authors.initials: JM
authors.lastname: Bell
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
authors.forename: P
authors.initials: P
authors.lastname: Herscovitch
authors.forename: W C
authors.initials: WC
authors.lastname: Eckelman
authors.forename: S I
authors.initials: SI
authors.lastname: Rapoport
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006935:Hypercapnia / Q000378:metabolism*; D016018:Least-Squares Analysis; D008253:Macaca mulatta; D008297:Male; D010743:Phospholipids / Q000378:metabolism*; D011869:Radioligand Assay; D012016:Reference Values; D014055:Tomography, Emission-Computed
chemical_list: D002250:Carbon Radioisotopes; D010743:Phospholipids; D016718:Arachidonic Acid