Psychopharmacological investigation on comorbidity influence between chronic neuropathic pain and depression

Abstract

The "International Association for the Study of Pain" (IASP) showed that about one in five people suffer from chronic pain worldwide. The effects on quality of life are overwhelming. Chronic neuropathic pain (NP) is one of the major health problems, which it can affect more than 20% of adults. Patients with NP are also affected with problems like insomnia (60%), difficulty concentrating (36%), depression (33%) and anxiety (27%). Furthermore, the NP and their comorbidity with depression are a challenging disease with respect to their treatment, thereby necessitating the use of experimental animal models for the elucidation of its underlying psychopharmacological mechanisms and the development of new therapeutic strategies to the. Considering the comorbidity between chronic pain and depression and the involvement of cortical areas as the medial prefrontal cortex (CLPC) in its modulation, animals with neuropathic pain (NP) induced by chronic constriction injury of the sciatic nerve (CCI) will be submitted the experimental predictive test for depression, the forced swimming test. Von Frey will be the nociceptive test will be performed, in which the nociceptive response after the forced swimming test also will be evaluated on the 21th day after the CCI. The pharmacological study will investigate the involvement of the glutamatergic, endovanniloid and endocannabinoid systems, as well as, NMDA receptors, TRPV1 channels and CB1 receptors of MPFC through the microinjection of agonist and antagonist at crescents concentrations, evaluating the influence of pretreatments of MPFC on the comorbidity between chronic neuropathic pain with stress and depression in an experimental model of chronic constriction DN induced by nervus ischiadicus in rats.