Depressive-like States Heighten the Aversion to Painful Stimuli in a Rat Model of Comorbid Chronic Pain and Depression

• DOI: 10.1097/aln.0b013e3182657b3e
• Publication Date: 2012-07-31T07:13:59Z
• Authors: Lidia Bravo; Juan Antonio Mico; Raquel Rey-Brea; Beatriz Pérez-Nievas; Juan Carlos Leza; Esther Berrocoso
• Keywords: Anhedonia; Chronic Stress; Cingulate cortex; Depression

Background Chronic pain and depression are two complex states with sensory/somatic emotional components, they may mutually exacerbate one another in conditions of comorbidity, leading to a poorer prognosis. Methods The authors have evaluated the sensory components rat model combining chronic constriction injury (CCI, neuropathic pain) unpredictable mild stress (CMS, an experimental depression). In addition, phosphorylation/activation extracellular signal-regulated kinases 1 2 neuronal density was also anterior cingulate cortex. Four groups were tested: sham-control, sham-CMS, CCI-control, CCI-CMS. Results CMS selectively heightens aversion painful experiences animals subjected CCI, as measured place escape/avoidance test at 20, 25, 30 min (CCI-CMS (mean±SEM): 75.68±3.32, 66.75±4.70, 77.54±3.60 vs. CCI-control: 44.66±6.07, 43.17±6.92, 52.83±5.92, respectively), conjunction increase accumulation (CCI-CMS: 4.17±0.52 sham-control: 0.96±0.05) decrease contrast, did not characteristic profile (anhedonia behavioral despair) rats CMS. Furthermore, enhances perception some specific modalities sensorial such cold allodynia but has no influence on mechanical threshold. Conclusions These findings support theory that leads dysfunction interpretation patients suffering pain. combined animal models pain-depression provide valuable tool study comorbidity depression.