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

Abstract

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 18F‐fluorodeoxyglucose‐positron emission tomography. We analyzed the differential effects of the anesthetics on 18F‐fluorodeoxyglucose uptake and pharmacokinetics in 33 rats using quantification methods: (a) the standardized uptake value, (b) voxel‐based analyses, and (c) 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 18F‐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 18F‐fluorodeoxyglucose and its Glut1‐mediated transport across the brain membranes (K1) were decreased in the KX group.

Tibial nerve stimulation increases vaginal blood perfusion and bone mineral density and yield load in ovariectomized rat menopause model

“…Ketamine-xylazine anesthesia has been demonstrated to reduce nerve conduction velocities [37] and cystometric responses [38] in mice. In addition to local interference at the nerve level, ketamine-xylazine reduces glucose metabolism in the brain [39], a site of extragonadal aromatization. Ketamine-xylazine anesthesia has also resulted in delayed recovery and possible hypoxia [40].…”

Comparison of different quantification methods for 18F-fluorodeoxyglucose-positron emission tomography studies in rat brains

“…It is known that hyperglycemia decreases [18F]FDG arterial inflow due to faster blood clearance and that the same injected dose of [18F]FDG does not guarantee the same arterial inflow of [18F]FDG 22. To minimize this problem, one can calculate the level of glucose consumption through the FUR that represents normalized glucose uptake by [18F]FDG arterial inflow and may neglect the influence of uptake by other [18F]FDG organs and of the patient's body weight 23-25. Our results, shown in Table 3 and Figure 4, indicate that there is an excellent correlation between the FUR and K i (Patlak) (r=0.9472, p <0.001) and FUR and K i (2TCM) (r=0.9385, p <0.001).…”

“…The procedures described in the present work are part of a small-animal PET experiment examining the effects of anesthetics on cerebral glucose metabolism 25. The current work addresses the issue of comparing different quantification methods.…”

P53 expression in ischemic rat models after the administration of ketamine and ketamine-xylazine

“…There might be a decrease in blood flows to the brain when ketamine-xylazine was given until ischemia occurred. Ketamine-xylazine can decrease the metabolism of glucose in the brain (Prando et al, 2019).…”