Abstract

An array of evidence indicates that long-term exposure to cocaine alters several components of the brain dopamine system. Because the release of dopamine in the nucleus accumbens (NAc) has been implicated in mediating the reinforcing effects of cocaine, changes in dopamine function can have profound effects on drug-seeking and drug-taking behavior. The present study examined the effects of the chronic self-administration of cocaine on the D1 family of dopamine receptors in the rhesus monkey. The brains of three rhesus monkeys that had intravenously self-administered an average of 1.35 mg/kg cocaine per day for 18-22 months were compared to the brains of three cocaine-naive controls. The in vitro quantitative autoradiographic technique was used to quantify binding densities of the D1 ligand [3H]SCH-23390 on cryostat-cut sections of fresh frozen tissue. In animals that self-administered cocaine, the density of D1 binding was significantly lower in the regions of the striatum at the level where the nucleus accumbens is most fully developed. The shell of the NAc showed the largest difference with significantly lower D1 binding also detected in adjacent regions of the caudate nucleus and the putamen. No differences were found in the rostral pole of the NAc or the dorsal striatum at that level. These findings suggest that chronic self-administration of cocaine can modulate the density of dopamine D1 receptors in specific portions of the primate striatum. Such changes might underlie some of the behavioral consequences, like drug dependence and craving, of long-term cocaine use.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

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.