J Orofac Pain 29 (2015), No. 2 30. Apr. 2015
J Orofac Pain 29 (2015), No. 2 (30.04.2015)
Persistent Neuropathic Pain Influences Persistence Behavior in Rats
Kniffin, Tracey C. / Danaher, Robert J. / Westlund, Karin N. / Ma, Fei / Miller, Craig S. / Carlson, Charles R.
Aims: To determine whether self-regulation can be studied successfully in a rodent model and whether persistent facial pain influences self-regulatory behavior.
Methods: Thirty male Sprague-Dawley rats, divided into two groups, (1) chronic constriction injury of the infraorbital nerve (CCI-ION) and (2) naïve, were used in a two-part behavioral paradigm of self-regulation. This paradigm consisted of both a cued go/no-go task (part one) and a persistence trial (part two). All animals were acclimated and trained for a period of 4 weeks prior to the experimental manipulation and then tested for a total of 5 weeks following experimental manipulation. Results were analyzed with t tests, one-way analysis of variance, and two-way, repeated measures analysis of variance.
Results: CCI-ION surgery induced significant mechanical hypersensitivity of the ipsilateral whisker pad that began 3 weeks postsurgery and persisted through the duration of the experiment (P < .001). At weeks 4 and 5 post-experimental manipulation, naïve animals demonstrated a significant decrease in lever presses during the persistence task (P < .05) compared to baseline, whereas CCI-ION animals did not (P = .55).
Conclusion: These results suggest that persistent pain influences behavioral regulation and that animals experiencing persistent pain may have difficulty adapting to environmental demands.
Keywords: chronic constrictive injury, infraorbital nerve, learning, orofacial pain, self-regulation