Brain incorporation of [11C]arachidonic acid in young healthy humans measured with positron emission tomography

• Published in: Journal of cerebral blood flow and metabolism Vol. 22; no. 12; pp. 1453 - 1462
• Main Authors: GIOVACCHINI, Giampiero, CHANG, Michael C. J, DOUDET, Doris J, HERSCOVITCH, Peter, ECKELMAN, William C, RAPOPORT, Stanley I, CARSON, Richard E, CHANNING, Michael A, TOCZEK, Maria, MASON, Alicja, BOKDE, Arun L. W, CONNOLLY, Catherine, VUONG, Bik-Kee, YING MA, DER, Margaret G
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.12.2002; Sage Publications Ltd
• Subjects: Adult; Arachidonic Acid - pharmacokinetics; Biological and medical sciences; Brain - diagnostic imaging; Brain - metabolism; Carbon Radioisotopes; Humans; Investigative techniques, diagnostic techniques (general aspects); Kinetics; Male; Medical sciences; Models, Biological; Nervous system; Phospholipases A - metabolism; Phospholipases A2; Phospholipids - metabolism; Radionuclide investigations; Second Messenger Systems - physiology; Tomography, Emission-Computed - methods; Radionuclide study; Human; Incorporation; Radiolabelling; Enzyme; Central nervous system; PET-Arachidonic acid- Second messenger-Phospholipase A2-Phospholipids- Modeling; Esterases; Method; Arachidonic acid; Metabolism; Phospholipase A; Carboxylic ester hydrolases; Signal transduction; Young adult; Second messenger; Hydrolases; Positron emission tomography; Brain (vertebrata)
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1097/00004647-200212000-00006

Arachidonic acid (AA) is an important second messenger involved in signal transduction mediated by phospholipase A2. The goal of this study was to establish an in vivo quantitative method to examine the role of AA in this signaling process in the human brain. A simple irreversible uptake model was derived from rat studies and modified for positron emission tomography (PET) to quantify the incorporation rate K* of [11C]AA into brain. Dynamic 60-minute three-dimensional scans and arterial input functions were acquired in 8 young healthy adults studied at rest. Brain radioactivity was corrected for uptake of the metabolite [11C]CO2. K* and cerebral blood volume (Vb) were estimated pixel-by-pixel and were calculated in regions of interest. K* equaled 5.6+/-1.2 and 2.6+/-0.5 microL x min(-1) x mL(-1) in gray and white matter, respectively. K* and Vb values were found to be unchanged with data analysis periods from 20 to 60 minutes. Thus, PET can be used to obtain quantitative images of the incorporation rate K* of [11C]AA in the human brain. As brain incorporation of labeled AA has been shown in awake rats to be increased by pharmacological activation associated with phospholipase A2-signaling, PET and [11C]AA may be useful to measure signal transduction in the human brain.