Abstract
Background: In a previous study in female rats, voluntary wheel running attenuated incubation of cocaine craving after 30 but not 3 days (Zlebnik and Carroll Zlebnik and Carroll, Psychopharmacology 232:3507–3413, 2015). The present study in male rats, using the same procedure, showed that wheel running reduced incubated craving after both 30 and 3 days of abstinence. Methods: Male rats self-administered i.v. cocaine (0.4 mg/kg) during 6-h sessions for 10 days. They were then moved from the operant chamber to a home cage with an attached running wheel or stationary wheel, for 6 h daily for a 3- or 30-day period when cocaine craving was hypothesized to incubate. Rats were then returned to the operant chamber for a 30-min test of cocaine seeking, or “craving,” indicated by responses on the former “drug” lever was formerly associated with drug stimulus lights and responses (vs. no drug stimuli), and lever responding was compared to responses on the “inactive” that was illuminated and counted lever pressing. Results: Mean wheel revolutions were similar across the 3- and 30-day incubation groups, when both groups of rats were given access to wheel running vs. access to a stationary wheel in controls. Subsequently, when rats were tested in the operant chamber for “relapse” responding (drug-lever responding) on the lever formerly associated with drug access, cocaine craving was reduced by recent running wheel access (vs. stationary wheel access) in both the 3- and 30-day wheel exposure groups. Conclusion: Voluntary, self-initiated, and self-sustained physical exercise reduced cocaine craving after short- (3 days) and long-term (30 days) abstinence periods in male rats that previously self-administered cocaine. This was contrasted with reduction of cocaine seeking in females after 30-day, but not 3-day, incubation periods under the wheel running vs. stationary wheel conditions in a previous study (Zlebnik and Carroll Zlebnik and Carroll, Psychopharmacology 232:3507–3413, 2015). These initial findings suggest males may be more sensitive to incubated craving for cocaine than females.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3819-3831 |
| Number of pages | 13 |
| Journal | Psychopharmacology |
| Volume | 239 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 2022 |
Bibliographical note
Funding Information:This research was supported by the National Institute on Drug Abuse grants P50 DA033942, R01 DA002486, and R01 DA003240 (MEC) and trainees who worked on the grant were supported by T32 DA07097 (Thomas Molitor, PI) and the University Medical Foundation, University of Minnesota.
Funding Information:
• These were 2 separate studies conducted 3 years apart. In the first study, only females were examined (P50 DA033942), as it was conducted under a grant supported by NIH Office of Research on Women’s Health. The present contribution focuses on males of the same age and identical experimental conditions as the 2015 study noted above. However, the present data on male animals were collected in 2018 to compare sex differences in addictive behavior.
Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Keywords
- Cocaine
- Cocaine craving
- Male rats
- Physical exercise
- Relapse model