Pain aversion and anxiety-like behavior occur at different times during the course of chronic inflammatory pain in rats

Abstract

Pain is considered a multidimensional conscious experience that includes a sensory component and a negative affective-motivational component. The negative affective-motivational component of pain is different from the sensory component and amplifies the pain experience. Nowadays, a significant number of preclinical research groups have focused their attention on the affective symptoms of pain. In the present study, we investigated the pain aversion and anxiety-like behavior of the complete Freund’s adjuvant (CFA)-induced chronic pain model. CFA rats experienced spontaneous pain during pain-paired conditioning (pain aversion) and spontaneous pain produces an affective response (anxiety-like behavior). Moreover, pain aversion was gradually attenuated, while the anxiety-like behavior increased in 4 weeks. Therefore, although the negative effect (including pain aversion and anxiety) is always associated with hyperalgesia, the manifestations of negative effect may follow different time courses, which may influence the progress of primary disease. The findings illustrate that targeted therapy should focus on a specific aspect in different stages of pain. Our study emphasizes the necessity of using multiple tests to study pain comorbidities.

Brain-Derived Neurotrophic Factor Precursor in the Hippocampus Regulates Both Depressive and Anxiety-Like Behaviors in Rats

“…Like the anxiogenic effect of neuropathic pain (43, 44), CFA injection induced persistent inflammatory pain, which developed the anxiety-like behavior 3 weeks after CFA injection. It is consistent with the studies reported previously (27, 45). Notably, the chronic inflammatory pain may affect locomotor activity.…”

Cannabidiol modulates serotonergic transmission and reverses both allodynia and anxiety-like behavior in a model of neuropathic pain

“…Clinical 57,81,84 and preclinical 40,41,49,62,74,90 studies have indicated strong comorbidity between chronic pain and anxiety. Furthermore, clinical studies have shown that CBD is effective at reducing anxiety.…”

Chronic Pain: Structural and Functional Changes in Brain Structures and Associated Negative Affective States

“…A study using a rat model with a chronic constriction injury reported that long-term pain led to an anxiety-like profile, increased responses to aversion, and impairments in cognitive tasks [39]. Wu et al reported that negative effects including pain aversion and anxiety were associated with hyperalgesia but that the manifestations of negative effects may occur over different time courses, suggesting that therapy should be targeted based on the different stages of pain and its comorbidities [40].…”