Effect of subcutaneous injection and oral voluntary ingestion of buprenorphine on post-operative serum corticosterone levels in male rats

Eur Surg Res. 2008;41(3):272-8. doi: 10.1159/000142372. Epub 2008 Jul 3.


Background: Adequate peri-operative analgesia may reduce post-operative stress response and improve recovery in laboratory animals. We have established a method involving repeated automated blood sampling, allowing quantification of serum corticosterone levels in rats for stress assessment without stress-inducing handling or restraint. In the present study, the effects of the commonly used route of buprenorphine administration (0.05 mg/kg injected subcutaneously) were compared with oral administration (0.4 mg/kg mixed with Nutella and orally administered by voluntary ingestion) in male Sprague-Dawley rats.

Methods: A catheter was placed in the jugular vein and attached to an Accusampler for automated blood sampling. During 96 h after surgery, blood was collected at specified time points. Pre- and post-operative body weights and water consumption were registered.

Results: Buprenorphine significantly suppressed levels of circulating corticosterone after the oral but not after the subcutaneous treatment. Both buprenorphine treatments had a positive impact on maintenance of body weight and water consumption, compared to the control group that received no buprenorphine.

Conclusion: The present investigation suggests that oral voluntary ingestion ad libitum is an efficacious, convenient and non-invasive way of administering peri-operative buprenorphine to rats, as judged by corticosteroid response and effects on body weight and water consumption.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Analgesia / methods
  • Analgesics, Opioid / administration & dosage*
  • Animals
  • Body Weight / drug effects
  • Buprenorphine / administration & dosage*
  • Corticosterone / blood*
  • Drinking / drug effects
  • Injections, Subcutaneous
  • Male
  • Postoperative Period
  • Rats
  • Rats, Sprague-Dawley
  • Self Administration
  • Stress, Physiological / drug effects*


  • Analgesics, Opioid
  • Buprenorphine
  • Corticosterone