Integrative SystemsIncreased immediate early gene activation in the basolateral amygdala following persistent peripheral inflammation.Morales-Medina, Julio Cesara; Rastogi, Ashutoshb; Mintz, Ericb,,d; Caldwell, Heather K.c,,dAuthor Information aCentro de Investigación en Reproducción Animal, CINVESTAV – Universidad Autónoma de Tlaxcala, México bBehavioral Neurobiology Laboratory, Department of Biological Sciences, Kent State University cLaboratory of Neuroendocrinology and Behavior, Department of Biological Sciences dSchool of Biomedical Sciences, Kent State University, Kent, USA Received 6 March 2020 Accepted 31 March 2020 Correspondence to Heather K. Caldwell, PhD, Department of Biological Sciences, Kent State University, PO Box 5190, Kent, Ohio 44242, USA, Tel: +330 672 3636; e-mail: firstname.lastname@example.org NeuroReport: July 10, 2020 - Volume 31 - Issue 10 - p 724-729 doi: 10.1097/WNR.0000000000001480 Buy Metrics Abstract Chronic pain results in a variety of neural adaptations, many of which are maladaptive and result in hypersensitivity to pain. In humans, this hypersensitivity can be debilitating and treatment options are limited. Fortunately, there are numerous animal models that mimic clinical populations and have the potential to aid in the evaluation of underlying mechanisms and ultimately the development of better treatments. One of these is the complete Freund’s adjuvant (CFA)-model of chronic inflammatory pain. In rodents, this model requires the injection of CFA into the hindpaw, muscle, or joint, which induces inflammation similar to what might be found in individuals with rheumatoid arthritis or tendonitis. While the mechanistic effects CFA on the spinal cord are well established, less is known about the effects of CFA on the brain. Thus, in this study, neuronal activation, as measured by c-Fos immunocytochemistry, in brain regions important to control of pain was evaluated. Animals that received CFA treatment, and tested 3 days later for mechanical allodynia and edema, had an increase in the number of c-Fos immunopositive cells in the basolateral amygdala, but not in any of the other brain regions that were evaluated. Given that the basolateral amygdala is known to be important for pain-related emotional responses, these data suggest that the CFA-model may provide an opportunity to further explore how pain affects this brain region at a mechanistic level, which in turn may shed light on what may be occurring in clinical populations. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.