Graduation Year

2005

Document Type

Thesis

Degree

M.A.

Degree Granting Department

Psychology

Major Professor

Cheryl Kirstein.

Keywords

Dopamine, Sucrose, Microdialysis, Neurochemistry, Nucleus accumbens septi, Development, Adolescence

Abstract

The long-term consequences of adolescent drug use in shaping a network primed for addiction is an issue of utmost importance. The use of cocaine during adolescent development could alter the normal growth of the reward system and affect the adult mesolimbic system, however, there is scant literature aimed at finding out if animals are more vulnerable to the adverse effects of drugs during adolescence. The present study investigated whether cocaine pretreatment in adolescent and adult rats produced differences in cocaine-induced neurochemical cross-sensitization to a naturally reinforcing substance in adulthood. To evaluate the responsivity of the mesolimbic system after repeated cocaine, sucrose was offered during the dialysis procedure and dialysate was collected. All saline pretreated rats had significant increases in DA levels compared to baseline levels and there were no difference in the age of pretreatment.

Rats pretreated with cocaine as adults also had significant increases in DA levels after sucrose. Interestingly, sucrose intake significantly enhanced DA levels in cocaine pretreated adolescent rats. The results from this experiment clearly show that in rats pretreated with cocaine during adolescence there is an enhance response of the DAergic system in response to a naturally reinforcing substance therefore; cocaine exposure during adolescence results in persistent long term changes in the mesolimbic pathway. Future studies need to ascertain the underlying mechanisms and their role in the process of addiction.

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