title: Small animal positron emission tomography during vagus nerve stimulation in rats: a pilot study.
abstract: Vagus nerve stimulation (VNS) is an effective neurophysiological treatment for patients with refractory epilepsy, however, the mechanism of action remains unclear. Small animal positron emission tomography (PET) permits the monitoring of biochemical processes during multiple scans in the same animal. The aim of this pilot study was to explore the potential of 2-[18F]-fluoro-2-deoxy-d-glucose (FDG)-PET to investigate the effect of acute and chronic VNS on glucose metabolism in the rat brain. One week after EEG and VNS electrode implantation, a baseline FDG-PET scan was acquired during which animals were not stimulated. Secondly, scans were taken after first activation of the VNS electrode (acute VNS) and after one week of continuous VNS (chronic VNS). On the same time points, images were obtained in a control group. After acquisition, PET images were manually fused with MRI data. Normalized brain activities and left/right activity ratios of different brain structures were compared between control measurements and VNS group. During acute VNS, glucose metabolism was significantly decreased in the left hippocampus (P<0.05). Significant increases were found in both olfactory bulbs (P<0.05). During chronic VNS, a significant decrease in left/right ratio in the striatum (P<0.05) was found. Acute and chronic VNS induced changes in glucose metabolism in regions important for seizure control (hippocampus and striatum). Our results promote further brain research on VNS using small animal PET in rats.
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Department of Neurology, Ghent University Hospital, Ghent, Belgium. Stefanie.Dedeurwaerdere@hotmail.com
authors.forename: Stefanie
authors.initials: S
authors.lastname: Dedeurwaerdere
authors.forename: Bart
authors.initials: B
authors.lastname: Cornelissen
authors.forename: Koen
authors.initials: K
authors.lastname: Van Laere
authors.forename: Kristl
authors.initials: K
authors.lastname: Vonck
authors.forename: Eric
authors.initials: E
authors.lastname: Achten
authors.forename: Guido
authors.initials: G
authors.lastname: Slegers
authors.forename: Paul
authors.initials: P
authors.lastname: Boon
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging*; D001923:Brain Chemistry / Q000502:physiology; D004558:Electric Stimulation; D004569:Electroencephalography; D007839:Functional Laterality / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D014630:Vagus Nerve / Q000502:physiology*
chemical_list: D005947:Glucose