Rats were acclimated to the animal facility for 3 days. On the 4th, 5th and 6th days, rats were subject to either MRI restraint and loud scanner noise, or exposure to the apparatus and quiet scanner noise (6 animals in each group) for 30 minutes per day. Restrained animals were placed in a fabric snuggle with head and tail protruding, and strapped into a Perspex MRI cradle, and non-restrained animals were exposed to and allowed to explore the restraint apparatus. On the 7th day, thermal sensitivity was measured with the Hargreaves apparatus, and on the 8th day, rats were tested for 5 minutes in the elevated zero maze. We found that, restraint training for 3 days causes changes in response to thermal and mechanical stimuli. We also measured blood corticosterone responses to the training and found that, compared to control animals, the restrained animals were showing signs of stress-produced analgesia. We also monitored animals for lasting effects of the restraint training by performing a pain test (formalin test) 12 days after the final training session, and are currently quantifying and analyzing the behavioral and brain responses to this test. The experiments in this project are now complete. Currently, behavioral video scoring is underway, brain tissue is being processed, and results are being prepared for publication.
| Low, Lucie A; Bauer, Lucy C; Pitcher, Mark H et al. (2016) Restraint training for awake functional brain scanning of rodents can cause long-lasting changes in pain and stress responses. Pain 157:1761-72 |
