Epidemiological data indicate that patients who experience a traumatic brain injury (TBI) have an elevated risk of developing a substance use disorder (SUD), but the underlying neurobiological connections remain unclear. To further understand the relationship between TBI and SUD, we investigated the effects of TBI on the abuse-related effects of oxycodone in preclinical models. Our evaluation utilized a lateral fluid percussion injury of moderate severity in adult male Sprague-Dawley rats. In the first aim, we tested the hypothesis that moderate TBI increases the risk for relapse to an opioid use disorder as measured by reinstatement of lever-pressing behavior following extinction in an intravenous oxycodone self-administration procedure. In the second aim, we tested the hypothesis that moderate TBI increases physiological dependence to oxycodone as measured by decreases in food-reinforced lever-pressing behavior and increases in other withdrawal behaviors in both precipitated withdrawal and spontaneous withdrawal. In tests for self-administration, brain-injured subjects, relative to non-injured subjects, showed no significant differences in the number of oxycodone-reinforced sessions required to meet stable maintenance criteria for lever-pressing behavior. Likewise, brain-injured subjects showed no significant differences in the number of non-reinforced sessions to meet extinction criteria for lever-pressing behavior relative to non-injured subjects. In tests for reinstatement, non-injured subjects reinstated responding under oxycodone-associated cue- and oxycodone prime-induced conditions, however, brain-injured subjects did not reinstate lever-pressing behavior under any conditions. In tests for physical dependence, brain-injured subjects showed no significant differences from non-injured subjects with regards to their mean withdrawal scores or food-reinforced lever-pressing behavior. Overall, these data suggest that brain-injured patients no significant pre-morbid history of opioid abuse are at a lesser risk of relapse to opioid use disorders. Moreover, the characteristic withdrawal syndrome in opioid-dependent patients may not contribute to continued opioid abuse to a greater degree in brain-injured patients than compared to non-injured patients.
| Identifer | oai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd-5265 |
| Date | 01 January 2016 |
| Creators | Varshneya, Neil |
| Publisher | VCU Scholars Compass |
| Source Sets | Virginia Commonwealth University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | © The Author |
Page generated in 0.0112 seconds