Reward/Drug Abuse Mechanisms

Neurochemical Research

, Volume 21, Issue 11, pp 1425-1435

First online:

Psychomotor stimulant- and opiate-induced c-fos mRNA expression patterns in the rat forebrain: Comparisons between acute drug treatment and a drug challenge in sensitized animals

  • Eileen J. CurranAffiliated withMental Health Research Institute, The University of Michigan
  • , Huda AkitAffiliated withMental Health Research Institute, The University of Michigan
  • , Stanley J. WatsonAffiliated withMental Health Research Institute, The University of Michigan

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Amphetamine-, cocaine-, and morphine-induced c-fos expression patterns were examined following an injection protocol that has previously been shown to produce behavioral sensitization and enhanced dopamine release in the striatal complex. Drug-specific c-fos patterns were observed in both acute and sensitization injection paradigms. A sensitization pretreatment schedule did, however, alter the c-fos expression patterns induced by all the drugs in the caudate putamen, nucleus accumbens, and the cerebral cortex. In some striatal and cortical regions, there was an increase or recruitment of cells expressing c-fos whereas in others there was an apparent decrease or inhibition. The somatosensory cortex was one area where pretreatment with all three drugs increased c-fos expression. The results suggest that the neuronal networks that are modulated by systemic drug injections in the sensitized animal differ from those affected by the initial drug exposure; areas of overlap may indicate common ‘sensitization’ circuits.

Key Words

Striatum somatosensory cortex amphetamine cocaine morphine