Articles: neuralgia.
-
J. Pharmacol. Exp. Ther. · Aug 2017
Cannabinoid CB2 Agonist GW405833 Suppresses Inflammatory and Neuropathic Pain through a CB1 Mechanism that is Independent of CB2 Receptors in Mice.
GW405833, widely accepted as a cannabinoid receptor 2 (CB2) agonist, suppresses pathologic pain in preclinical models without the unwanted central side effects of cannabinoid receptor 1 (CB1) agonists; however, recent in vitro studies have suggested that GW405833 may also behave as a noncompetitive CB1 antagonist, suggesting that its pharmacology is more complex than initially appreciated. Here, we further investigated the pharmacologic specificity of in vivo antinociceptive actions of GW405833 in models of neuropathic (i.e., partial sciatic nerve ligation model) and inflammatory (i.e., complete Freund's adjuvant model) pain using CB2 and CB1 knockout (KO) mice, their respective wild-type (WT) mice, and both CB2 and CB1 antagonists. GW405833 (3, 10, and 30 mg/kg i.p.) dose dependently reversed established mechanical allodynia in both pain models in WT mice; however, the antiallodynic effects of GW405833 were fully preserved in CB2KO mice and absent in CB1KO mice. ⋯ GW405833 (30 mg/kg i.p.) was also inactive in a tetrad of tests measuring cardinal signs of CB1 activation. Additionally, unlike rimonabant (10 mg/kg i.p.), GW405833 (10 mg/kg, i.p.) did not act as a CB1 antagonist in vivo to precipitate withdrawal in mice treated chronically with Δ9-tetrahydrocannabinol. The present results suggest that the antiallodynic efficacy of GW405833 is CB1-dependent but does not seem to involve engagement of the CB1 receptor's orthosteric site.
-
Semin. Arthritis Rheum. · Aug 2017
Review Meta AnalysisPrevalence of neuropathic pain in knee or hip osteoarthritis: A systematic review and meta-analysis.
Discordance between radiographic and pain severity in osteoarthritis (OA) has led researchers to investigate other pain mechanisms, including neuropathic pain. Accurate identification of any neuropathic pain in hip or knee OA is important for appropriate management, but neuropathic pain prevalence is unknown. We aimed to obtain an overall prevalence estimate by systematically reviewing and meta-analysing the prevalence of neuropathic pain in people with hip or knee OA. ⋯ Neuropathic pain prevalence in people with knee or hip OA is considerable at 23%, and may be higher after other potential causes of neuropathic pain are excluded. Concerns regarding the validity of neuropathic pain questionnaires, selection bias, methodological quality and study heterogeneity suggest caution with interpretation of these findings. Prevalence studies using standardised criteria for neuropathic pain are required.
-
Neuropathic pain after spinal surgery, the so-called failed back surgery syndrome (FBSS), is a frequently observed troublesome disease entity. Although medications may be effective to some degree, many patients continue experiencing intolerable pain and functional disability. Only gabapentin has been proven effective in patients with FBSS. ⋯ Percutaneous epidural adhesiolysis has also shown good clinical outcomes; however, its effects persisted for only a short period. Because none of the current methods provide absolute superiority in terms of clinical outcomes, a multidisciplinary approach is required to manage this complex disease. Further studies concerning the etiology, diagnosis, treatment, and cost effectiveness of FBSS are warranted to deepen our understanding of this condition.
-
Spinal cord stimulation (SCS) is a recognized management option for patients with refractory neuropathic pain. Despite randomized controlled trials reporting the effectiveness of SCS, there is a lack of long-term data reflecting usual SCS practice. The aim of this study is to present the long-term outcomes of a cohort of patients from a single centre undertaking SCS with devices from a single manufacturer. ⋯ Patients with neuropathic pain undertaking SCS experience long-term reductions in pain intensity and increases in health utility and associated QALY gains. The findings from this study associated with the increased longevity of rechargeable SCS devices suggest that the cost-effectiveness of SCS may become increasingly favourable when compared with conventional medical management.
-
Musculoskelet Sci Pract · Aug 2017
Comparative StudyThe diagnostic accuracy and test-retest reliability of the Dutch PainDETECT and the DN4 screening tools for neuropathic pain in patients with suspected cervical or lumbar radiculopathy.
It is important to identify neuropathic pain early to guide treatment decisions and prevent chronicity. There is lack of evidence whether the Dutch painDETECT questionnaire and Douleure Neuropathique en 4 questions (DN4) can adequately assess neuropathic pain. ⋯ Diagnosis, Level 1B.