Effects of subanesthetic ketamine on regional cerebral glucose metabolism in humans

The authors have recently shown with positron emission tomography that subanesthetic doses of racemic ketamine increase cerebral blood flow but do not affect oxygen consumption significantly. In this study, the authors wanted to assess the effects of racemic ketamine on regional glucose metabolic ra...

Full description

Saved in:
Bibliographic Details
Published in:Anesthesiology (Philadelphia) 2004-05, Vol.100 (5), p.1065-1071
Main Authors: LANSJO, Jaakko W, SALMI, Elina, SCHEININ, Harry, KAISTI, Kaike K, AALTO, Sargo, HINKKA, Susanna, AANTAA, Riku, OIKONEN, Vesa, VILJANEN, Tapio, KURKI, Timo, SILVANTO, Martti
Format: Article
Language:English
Subjects:
Adult
Analysis of Variance
Anesthesia
Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy
Anesthetics, Dissociative - administration & dosage
Biological and medical sciences
Brain - drug effects
Brain - metabolism
Energy Metabolism - drug effects
Energy Metabolism - physiology
Fluorodeoxyglucose F18 - metabolism
Glucose - metabolism
Humans
Ketamine - administration & dosage
Male
Medical sciences
Tomography, Emission-Computed - methods
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The authors have recently shown with positron emission tomography that subanesthetic doses of racemic ketamine increase cerebral blood flow but do not affect oxygen consumption significantly. In this study, the authors wanted to assess the effects of racemic ketamine on regional glucose metabolic rate (rGMR) in similar conditions to establish whether ketamine truly induces disturbed coupling between cerebral blood flow and metabolism. 18F-labeled fluorodeoxyglucose was used as a positron emission tomography tracer to quantify rGMR on 12 brain regions of interest of nine healthy male volunteers at baseline and during a 300-ng/ml ketamine target concentration level. In addition, voxel-based analysis was performed for the relative changes in rGMR using statistical parametric mapping. The mean +/- SD measured ketamine serum concentration was 326.4+/-86.3 ng/ml. The mean arterial pressure was slightly increased (maximally by 16.4%) during ketamine infusion (P < 0.001). Ketamine increased absolute rGMR significantly in most regions of interest studied. The greatest increases were detected in the thalamus (14.6+/-15.9%; P = 0.029) and in the frontal (13.6+/-13.1%; P = 0.011) and parietal cortices (13.1+/-11.2%; P = 0.007). Absolute rGMR was not decreased anywhere in the brain. The voxel-based analysis revealed relative rGMR increases in the frontal, temporal, and parietal cortices. Global increases in rGMR seem to parallel ketamine-induced increases in cerebral blood flow detected in the authors' earlier study. Therefore, ketamine-induced disturbance of coupling between cerebral blood flow and metabolism is highly unlikely. The previously observed decrease in oxygen extraction fraction may be due to nonoxidative glucose metabolism during ketamine-induced increase in glutamate release.
ISSN:0003-3022
1528-1175
DOI:10.1097/00000542-200405000-00006