Repeated amphetamine exposure induces sensitization and may also alter impulsivity
Amphetamine (AMPH) is a psychostimulant drug that can produce feelings of euphoria and alertness. Fernandez-Espejo (2006) suggests that psychostimulant drugs induce a strong dependence, manifested as tolerance at a neurobiological level. While tolerance is an important behavior of drug abusers, this particular experiment focused on sensitization. Sensitization is an increase in responsiveness after subsequent exposure to the same or lower doses of the drug. Therefore, our interest is to find out if after repeated AMPH exposure rats experience a decrease in locomotor activity (distance traveled), but an increase in stereotypy (repetitive). Sensitization was measured comparing their behavior between day two (first injection of d-amphetamine) and day 20 (tenth injection). In addition, rats were trained to learn the baseline of an operant conditioning task (delay discounting task), which consequently led to answer if repeated AMPH exposure cause changes in rat's behavior during the task. After rats were exposed to d-amphetamine, they experienced a decrease in locomotor activity and an increase in stereotypy. Rats didn't exhibit any differences in learning the baseline of the operant conditioning task. In the future, this study will aid in answering of whether or not AMPH increases impulsivity.
School:
University of Puerto Rico at Ponce
Department:
Psychology
Research Advisor:
Joshua M. Gulley
Department of Research Advisor:
Psychology and Neuroscience
Year of Publication:
2007