Factors underlying natural reward devaluation by cocaine: effects of dose and exercise Public Deposited

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  • March 19, 2019
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  • Stevenson, Jennifer
    • Affiliation: College of Arts and Sciences, Department of Psychology and Neuroscience
Abstract
  • In a preclinical model developed in the Carelli lab, when a palatable saccharin solution predicts impending, but delayed, cocaine availability the saccharin solution becomes devalued, as evidenced by the emergence of aversive taste reactivity during intraoral tastant infusion (Wheeler et al. 2008, 2011). Importantly, this negative affective state predicts the motivation to self-administer cocaine. The primary goal of this work is to extend the current knowledge of this preclinical model of natural reward devaluation and examine several other variables that may influence this process. In the original set of studies (Wheeler et al., 2008, 2011) only a single dose of cocaine was used. The first aim examined if rats receiving varying doses (0.167, 0.33, 0.66 mg/inf) of cocaine paired to the same concentration of saccharin (0.15%), would alter taste reactivity to the predictive cue in a dose-dependent manner. This study revealed that the emergence of negative affect and the associated increase in motivation for the drug was not dependent on cocaine dose. Exercise has been shown to reduce cocaine-seeking in animal models. Additional studies examined if exercise (i.e., access to a running wheel in their home cage), either following (Aim 2) or prior to (Aim 3) training on the preclinical model would reverse or attenuate the development of the negative affective state, and the motivation to consume cocaine. The results of Aim 2 indicate a trend toward a protective effect against the established negative affective state, however these results were not strong. Further, exercise had some protective effect against the motivation to consume cocaine when rats were reintroduced to the paradigm, although it did not completely reverse the negative affective state. The results of Aim 3 showed exercise does have a protective effect against the development of the negative affective state in this model, however, the motivation to consume cocaine continued after it had developed. Taken together, the results of these studies indicate that although the development of the negative affective state observed in our preclinical model is not cocaine dose-dependent, it can be altered to some degree by physical activity.
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  • In Copyright
Advisor
  • Daughters, Stacey
  • Picker, Mitchell
  • Dykstra, Linda A.
  • Lysle, Donald
  • Carelli, Regina
Degree
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2015
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  • Chapel Hill, NC
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