Abstract
One hypothetical model for a mechanism of drug dependence involves the development of an adaptive process that is initiated to counter the acute effects of the drug. This adaptive process persists after the drug has been cleared from the brain, leaving an opposing reaction unopposed (abstinence signs). From a motivational perspective a particularly attractive hypothesis has been that of opponent process theory (32). Here many reinforcers elicit positive affective and hedonic processes that are opposed by negative affective and hedonic processes. Thus the intense pleasure of the opiate drug "rush" or "high" would be opposed by aversive withdrawal symptoms. The present paper presents neurobiological evidence to support the opponent process concept and suggests neural circuitry that may be involved. The region of the nucleus accumbens in the forebrain of the rat has been shown to be a particularly sensitive substrate not only for the acute reinforcing properties of opiate drugs, but also for the response disruptive effects of opiate antagonists in opiate dependent rats. This region also appears to be particularly sensitive to the aversive stimulus effects of opiate antagonists using a place aversion measure in dependent rats. These results suggest that the region of the nucleus accumbens and its neural circuitry may be an important neural substrate for both the positive and negative motivational aspects of drug dependence.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.