DeltaFosB accumulation in ventro-medial caudate underlies the induction but not the expression of behavioral sensitization by both repeated amphetamine and stress

• Published in: The European journal of neuroscience Vol. 27; no. 1; pp. 191 - 201
• Main Authors: Conversi, D., Bonito-Oliva, A., Orsini, C., Colelli, V., Cabib, S.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-01-2008
• Subjects: accumbens core; Amphetamine - administration & dosage; Analysis of Variance; Animals; Behavior, Animal - drug effects; Caudate Nucleus - drug effects; Central Nervous System Stimulants - administration & dosage; Drug Administration Schedule; FosB/DeltaFosB; Gene Expression - drug effects; inducible transcription factors; Male; Mice; Mice, Inbred C57BL; Motor Activity - drug effects; mouse; Oncogene Proteins v-fos - metabolism; plasticity; Proto-Oncogene Proteins c-fos - metabolism; restraint; Stress, Physiological - metabolism; Stress, Physiological - pathology; Stress, Physiological - physiopathology
• ISSN: 0953-816X; 1460-9568
• DOI: 10.1111/j.1460-9568.2007.06003.x

Both repeated psychostimulants and stress have the ability to promote behavioral sensitization, i.e. enhanced behavioral response to drug challenge. To test whether the behavioral phenotype is also accompanied by similar neuroplastic adaptations, the present study evaluated changes in Fos and FosB/DeltaFosB transcription factors induced in the brain of C57BL/6J mice behaviorally sensitized by repeated amphetamine or repeated restraint stress. Groups of mice received repeated injections of d‐amphetamine or saline in group‐specific environments. Different groups of mice experienced 2 h of restraint daily for 10 consecutive days. Amphetamine‐ pre‐treated mice, drug‐challenged in the environment in which they received drug treatments (Paired), as well as repeatedly stressed mice expressed robust sensitization to the locomotor effects of amphetamine. Both stress‐ and amphetamine‐pre‐treated groups showed changes in amphetamine‐induced Fos expression; however, none of these changes was shared by the two sensitizing treatments. Instead, accumulation of FosB/DeltaFosB immunoreactivity in the ventro‐medial caudate was common to both pre‐treatments. These results support the hypothesis that a common neuroadaptive process involving DeltaFosB accumulation in the ventro‐medial caudate underlies the induction but not the expression of behavioral sensitization by different conditions.