Effects of ketamine/xylazine and isoflurane on rat brain glucose metabolism measured by 18 F-fluorodeoxyglucose-positron emission tomography.

The aim of the present study was to investigate changes in glucose metabolism in male Wistar rats induced by the anesthetics isoflurane and ketamine combined with xylazine via 18 F-fluorodeoxyglucose-positron emission tomography. We analyzed the differential effects of the anesthetics on 18 F-fluorodeoxyglucose uptake and pharmacokinetics in 33 rats using quantification methods: 1) the standardized uptake value, 2) voxel-based analyses, and 3) kinetic analysis. Both anesthetics reduced glucose uptake in the entire brain. The voxel-based analyses detected smaller uptake reductions in the bilateral primary somatosensory system cortex and part of the limbic system in the ketamine-xylazine (KX) group and in the vestibular nucleus in the isoflurane group. Through kinetic analysis, we found that the volume of distribution and the membrane transport rate K1 were reduced in the KX group. Through various methods of 18 F-fluorodeoxyglucose-positron emission tomography quantification, the present study found that anesthesia with the ketamine-xylazine combination induced a global reduction of glucose metabolism compared with isoflurane; this reduction of metabolism was relatively lower in the primary somatosensory cortex and part of the limbic system. The volume of distribution of 18 F-fluorodeoxyglucose and its Glut1-mediated transport across the brain membranes (K1 ) were decreased in the KX group. This article is protected by copyright. All rights reserved.