Pain
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Recent data suggest that comorbid substance use disorders (SUDs) are common among chronic non-cancer pain (CNCP) patients; however, prevalence rates vary across studies and findings are limited regarding treatment options for CNCP patients with comorbid SUD. The purpose of this systematic review is to assess the prevalence, associated demographic and clinical characteristics, and treatment outcomes for CNCP patients with comorbid SUD. We conducted searches from Ovid MEDLINE, PsychINFO, and PubMED from 1950 through February 2010 and retrieved the references. ⋯ Limited data are available to identify predictors of treatment outcome. Although clinical experience and research suggests that SUDs are common among CNCP patients, only limited data are available to guide clinicians who treat this population. Research is needed to increase understanding of the prevalence, correlates, and responses to treatment of CNCP patients with comorbid SUDs.
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Spinal cord injury (SCI) commonly results in the development of neuropathic pain, which can dramatically impair the quality of life for SCI patients. SCI-induced neuropathic pain can be manifested as both tactile allodynia (a painful sensation to a non-noxious stimulus) and hyperalgesia (an enhanced sensation to a painful stimulus). The mechanisms underlying these pain states are poorly understood. ⋯ Furthermore, both intrathecal gabapentin treatment and blocking SCI-induced Ca(v)α2δ-1 protein upregulation by intrathecal Ca(v)α2δ-1 antisense oligodeoxynucleotides could reverse tactile allodynia in SCI rats. These findings support that SCI-induced Ca(v)α2δ-1 upregulation in spinal dorsal horn is a key component in mediating below-level neuropathic pain states, and selectively targeting this pathway may provide effective pain relief for SCI patients. Spinal cord contusion injury caused increased calcium channel Ca(v)α2δ-1 subunit expression in dorsal spinal cord that contributes to neuropathic pain states.
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Our previous studies show that attention to painful cutaneous laser stimuli is associated with functional connectivity between human primary somatosensory cortex (SI), parasylvian cortex (PS), and medial frontal cortex (MF), which may constitute a pain network. However, the direction of functional connections within this network is unknown. We now test the hypothesis that activity recorded from the SI has a driver role, and a causal influence, with respect to activity recorded from PS and MF during attention to a laser. ⋯ LFP at some electrode sites (critical sites) exerted GRC influences upon signals at multiple widespread electrodes, both in other cortical areas and within the area where the critical site was located. Critical sites may bind these areas together into a pain network, and disruption of that network by stimulation at critical sites might be used to treat pain. Electrical activity recorded from the somatosensory cortex drives activity recorded elsewhere in the pain network and may bind the network together; disruption of that network by stimulation at critical sites might be used to treat pain.