Electronic Theses and Dissertations

Identifier

1220

Date

2014

Date of Award

7-22-2014

Document Type

Thesis

Degree Name

Master of Science

Major

Psychology

Committee Chair

Helen Joan Sable

Committee Member

J Gayle Beck

Committee Member

Charles D Blaha

Abstract

Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxins known to adversely impact human health. Ortho-substituted PCBs in particular are known to affect the nervous system and more specifically the brain dopaminergic system. Developmental PCB exposure in rats has been shown to produce alterations in the dopamine system that persists into adulthood. The reinforcing properties of psychostimulants are typically modulated via the dopaminergic system, so this project was conducted to evaluate whether perinatal PCB exposure would alter intravenous self-administration (IVSA) for the psychostimulant cocaine. Long Evans rats were perinatally exposed to 6 mg/kg/day or 3 mg/kg/day of PCBs throughout gestation and lactation and compared to controls. Rats were trained to lever press for a food reward in an operant chamber under a fixed-ratio 5 (FR5) schedule and later underwent jugular catheterization. Food rewards were switched for infusions of 250 µg of cocaine, but the FR5 response requirement to earn the reinforcer on the active lever remained. PCB-exposed males exhibited an increase in active lever presses and cocaine infusions during the acquisition phase of cocaine intravenous self-administration. While sex effects were repeatedly seen, no PCB-related differences were observed during the maintenance IVSA sessions, during examination of the dose-response relationship, or during progressive ratio sessions. Overall, these results indicate that perinatal PCB exposure can enhance early cocaine drug-seeking, particularly in males, as demonstrated by an increase in active lever presses and infusions in males perinatally exposed to PCBs. This effect is believed to be due to PCB-associated dopaminergic dysfunction.

Comments

Data is provided by the student.

Library Comment

dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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