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Behavioural Brain Research 176 (2007) 251258 Research report

Summary: Behavioural Brain Research 176 (2007) 251258
Research report
Activation in extended amygdala corresponds to altered hedonic
processing during protracted morphine withdrawal
Glenda C. Harris, Gary Aston-Jones
Department of Psychiatry, University of Pennsylvania, Translational Research Labs/3403, 125 S 31st Street, Philadelphia, PA 19104, United States
Received 1 August 2006; received in revised form 6 October 2006; accepted 7 October 2006
Available online 22 November 2006
Previously we reported that during protracted morphine abstinence rats show reduced conditioned place preferences (CPP) for food-associated
environments, compared to non-dependent subjects. To determine the brain regions involved in this altered reward behavior, we examined neural
activation (as indexed by Fos-like proteins) induced by a preference test for a food-associated environment in 5-week morphine-abstinent versus
non-dependent animals. The results indicate that elevated Fos expression in the anterior cingulate cortex (Cg) and basolateral amygdala (BLA)
correlated positively with preference behavior in all groups. In contrast, Fos expression in stress-associated brain areas, including the ventral lateral
bed nucleus of the stria terminalis (VL-BNST), central nucleus of the amygdala (CE), and noradrenergic (A2) neurons in the nucleus tractus
solitarius (NTS) was significantly elevated only in morphine-abstinent animals. Furthermore, the number of Fos positive neurons in these areas was
found to correlate negatively with food preference in abstinent animals. These results indicate that the altered hedonic processing during protracted
morphine withdrawal leading to decreased preference for cues associated with natural rewards may involve heightened activity in stress-related
brain areas of the extended amygdala and their medullary noradrenergic inputs.
2006 Elsevier B.V. All rights reserved.


Source: Aston-Jones, Gary - Department of Neurosciences, Medical University of South Carolina


Collections: Biology and Medicine