Distinct patterns of 
FosB induction in brain by drugs of abuseSynapse 358-369, 2008.
The transcription factor
FosB accumulates and persists in brain in response to chronic stimulation. This accumulation after chronic exposure to drugs of abuse has been demonstrated previously by Western blot most dramatically in striatal regions, including dorsal striatum (caudate/putamen) and nucleus accumbens.
In the present study, we used immunohistochemistry to define with greater anatomical precision the induction ofFosB throughout the rodent brain after chronic drug treatment. We also extended previous research involving cocaine, morphine, and nicotine to two additional drugs of abuse, ethanol and 9-tetrahydrocannabinol (9-THC, the active ingredient in marijuana).
We show here that chronic, but not acute, administration of each of four drugs of abuse, cocaine, morphine, ethanol, and9-THC, robustly induces FosB in nucleus accumbens, although different patterns in the core vs. shell subregions of this nucleus were apparent for the different drugs.
The drugs also differed in their degree ofFosB induction in dorsal striatum. In addition, all four drugs induced FosB in prefrontal cortex, with the greatest effects observed with cocaine and ethanol, and all of the drugs induced FosB to a small extent in amygdala.
Furthermore, all drugs inducedFosB in the hippocampus, and, with the exception of ethanol, most of this induction was seen in the dentate. Lower levels of FosB induction were seen in other brain areas in response to a particular drug treatment.
These findings provide further evidence that induction ofFosB in nucleus accumbens is a common action of virtually all drugs of abuse and that, beyond nucleus accumbens, each drug induces FosB in a region-specific manner in brain.
Read Full Abstract
Request Reprint E-Mail: eric.nestler@utsouthwestern.edu
______________________________________________________________
The transcription factor
FosB accumulates and persists in brain in response to chronic stimulation. This accumulation after chronic exposure to drugs of abuse has been demonstrated previously by Western blot most dramatically in striatal regions, including dorsal striatum (caudate/putamen) and nucleus accumbens.In the present study, we used immunohistochemistry to define with greater anatomical precision the induction of
FosB throughout the rodent brain after chronic drug treatment. We also extended previous research involving cocaine, morphine, and nicotine to two additional drugs of abuse, ethanol and 9-tetrahydrocannabinol (9-THC, the active ingredient in marijuana).We show here that chronic, but not acute, administration of each of four drugs of abuse, cocaine, morphine, ethanol, and
9-THC, robustly induces FosB in nucleus accumbens, although different patterns in the core vs. shell subregions of this nucleus were apparent for the different drugs.The drugs also differed in their degree of
FosB induction in dorsal striatum. In addition, all four drugs induced FosB in prefrontal cortex, with the greatest effects observed with cocaine and ethanol, and all of the drugs induced FosB to a small extent in amygdala.Furthermore, all drugs induced
FosB in the hippocampus, and, with the exception of ethanol, most of this induction was seen in the dentate. Lower levels of FosB induction were seen in other brain areas in response to a particular drug treatment.These findings provide further evidence that induction of
FosB in nucleus accumbens is a common action of virtually all drugs of abuse and that, beyond nucleus accumbens, each drug induces FosB in a region-specific manner in brain.Read Full Abstract
Request Reprint E-Mail: eric.nestler@utsouthwestern.edu
______________________________________________________________
