INVESTIGATOR: Michael Taffe, Ph.D.
STUDY LOCATION: University of California, San Diego
PROJECT TITLE: Cannabinoid alteration of the reinforcing effects of exercise in rats
FUNDING SOURCE: Center for Medicinal Cannabis Research
PROJECT TYPE: Preclinical Study
STATUS: Active
ABSTRACT:
Background-Significance: Physician and public health prescriptions for increased exercise are consistent with evidence it can improve many conditions, including substance use disorders. These often have mixed success due to variability in sustaining exercise regimens. We’ve shown ?9-tetrahydrocannabinol (THC) enhances the reinforcing effects of intravenous self- administration of opioids in rats and that wheel activity can diminish stimulant and opioid self-administration. Post-exercise elevations of endocannabinoid levels suggest a potential for THC to enhance the reward value of exercise
Hypothesis: THC enhances the reinforcing properties of physical exercise, thereby strengthening its ability to diminish drug self- administration. Innovation: The project will innovate first by using a method we have pioneered for an e-cigarette based drug inhalation model for rats that continues to drive the field forward via a delivery method that has been widely adopted by human consumers of THC. The project will innovate conceptually for clinical approaches by placing emphasis on leveraging reward processes to enhance exercise consistency or intensity.
Methods: Groups (N=12) of male and female rats will be exposed to daily THC, or vehicle, vapor inhalation prior to wheel access for 2, 6 or 23 h. Experiments in the first Aim will determine if the escalation of wheel activity, which takes place over several weeks, is potentiated by THC. Experiments in the second Aim will determine if THC-enhancement of wheel activity further increases the impact of prior or concurrent wheel access on the intravenous self-administration of oxycodone or methamphetamine. Rats will be randomized to vapor inhalation conditions (vehicle, THC) and wheel access conditions for the experiments. The primary dependent variables will be wheel rotations in Aim 1 and drug infusions obtained in Aim 2, which will be assessed by ANOVA using between groups factors for treatment condition and sex.
Implications: These studies will provide new insight into how THC may enhance the reinforcing effects of physical exercise and how physical exercise may diminish the rewarding effect of drugs.