1. ¹Section on Neuroadaptation and Protein Metabolism, National Institute of Mental Health, Bethesda, Maryland, USA
2. ²PET Department, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
3. ³Office of the Clinical Director, National Institute of Mental Health, Bethesda, Maryland, USA
4. ⁴Department of Anesthesia and Surgical Services, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, Maryland, USA

Correspondence: Dr S Bishu, Section on Neuroadaptation and Protein Metabolism, National Institute of Mental Health, Bldg 10, Rm 2D54, 10 Center Drive, Bethesda, MD 20892-1298, USA. E-mail: bishus@mail.nih.gov

Received 25 September 2008; Revised 7 January 2009; Accepted 8 January 2009; Published online 18 February 2009.

Abstract

We report regional rates of cerebral protein synthesis (rCPS) in 10 healthy young males, each studied under two conditions: awake and anesthetized with propofol. We used the quantitative L-[1-¹¹C]leucine positron emission tomography (PET) method to measure rCPS. The method accounts for the fraction () of unlabeled leucine in the precursor pool for protein synthesis that is derived from arterial plasma; the remainder comes from proteolysis of tissue proteins. Across 18 regions and whole brain, mean differences in rCPS between studies ranged from -5% to 5% and were within the variability of rCPS in awake studies (coefficient of variation range: 7% to 14%). Similarly, differences in (range: 1% to 4%) were typically within the variability of (coefficient of variation range: 3% to 6%). Intersubject variances and patterns of regional variation were also similar under both conditions. In propofol-anesthetized subjects, rCPS varied regionally from 0.980.12 to 2.390.23 nmol g^-1 min^-1 in the corona radiata and in the cerebellum, respectively. Our data indicate that the values, variances, and patterns of regional variation in rCPS and measured by the L-[1-¹¹C]leucine PET method are not significantly altered by anesthesia with propofol.