Comparative benefits of social housing and buprenorphine on wheel running depressed by morphine withdrawal in rats.

RATIONALE

Social support and opioid replacement therapy are commonly used to treat opioid withdrawal.

OBJECTIVE

The present study tested the hypothesis that social housing and buprenorphine administration can restore wheel running depressed by morphine withdrawal in rats.

RESULTS

Experiment 1 assessed disruptive side effects of buprenorphine and found that administration of low doses (3.2, 10, & 32 µg/kg, s.c.) had no impact on voluntary wheel running. Experiment 2 assessed the impact of social housing and acute buprenorphine administration (10 µg/kg) on morphine withdrawal. Two 75 mg morphine pellets were implanted for 3 days to induce dependence. Removal of the morphine pellets caused a decrease in body weight, increase in wet dog shakes, and depression of wheel running during the normally active dark phase of the circadian cycle. Social housing restored wheel running and reduced the number of wet dog shakes but did not affect body weight. Administration of buprenorphine restored wheel running depressed by morphine withdrawal for 2 days in individually housed rats and produced time-dependent changes in socially housed rats: Depression of wheel running in the 3 h following administration and restoration of running subsequently compared to saline-treated controls.

CONCLUSIONS

The impact of buprenorphine and social housing to reduce the effect of morphine withdrawal in rats is consistent with the use of opioid substitution therapy and psychotherapy/social support to treat opioid withdrawal in humans. These data provide further validation for the clinical relevance for the use of wheel running to assess spontaneous opioid withdrawal.