Abstract
1204
Objectives The endocannabinoid system is a potential target in the treatment of anorexia nervosa. We aimed to investigate the endocannabinoid system using [18F]MK-9470 CB1 receptor PET imaging in an activity based rat model of anorexia, in comparison to motor- and food-related control conditions and in relation to behavioral variables.
Methods 44 female 6 week-old Wistar rats were divided into 4 groups, 1 ABA group (n=14) and 3 control conditions (3x n=10). The first group was subjected to food restriction in the presence of a running wheel (ABA), the second one to food restriction without wheel (DIET), the third one to a normal diet with wheel (WHEEL) and the last group had a normal diet and no running wheel (CONTROL). After 10 days, microPET data were acquired using 21.4+/-2.2 MBq [18F]MK-9470. Reconstructed data were spatially normalized,mSUV was used as index of CB1R availability. Volume-of-interest and SPM2 analysis was done.
Results Cerebral CB1R binding was significantly increased in all cortical and subcortical areas in ABA compared to WHEEL (+51%) and CONTROL (+53%) (pheight<0.05 FWE corrected). The difference between ABA compared to DIET (+20%) was not significant. Average food intake,running activity and weight loss were not correlated with CB1R binding.
Conclusions These results suggest that the combination of food restriction and physical activity induces major changes in CB1R availability in ABA rats. This study points towards CB1R upregulation as a compensation mechanism in ABA, and may suggest a beneficial role for endocannabinoid augmenting pharmacotherapy (e.g. endocannabinoid degradation blockers) in this animal model of anorexia.
Research Support Research Council KU Leuven (OT/05/58), EU FP6-project DIMI, LSHB-CT-2005-512146.
- © 2009 by Society of Nuclear Medicine