Articles: neuralgia.
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T-type Ca channels (T channels), particularly Cav3.2 among the 3 isoforms, play a role in neuropathic and visceral pain. We thus characterized the effects of RQ-00311651 (RQ), a novel T-channel blocker, in HEK293 cells transfected with human Cav3.1 or Cav3.2 by electrophysiological and fluorescent Ca signaling assays, and also evaluated the antiallodynic/antihyperalgesic activity of RQ in somatic, visceral, and neuropathic pain models in rodents. RQ-00311651 strongly suppressed T currents when tested at holding potentials of -65 ∼ -60 mV, but not -80 mV, in the Cav3.1- or Cav3.2-expressing cells. ⋯ The analgesic and antihyperalgesic/antiallodynic doses of oral and i.p. RQ did not significantly affect the locomotor activity and motor coordination. Together, RQ is considered a state-dependent blocker of Cav3.1/Cav3.2 T channels and may serve as an orally available analgesic for treatment of neuropathic and inflammatory pain including distinct visceral pain with minimum central side effects.
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Endometriosis is a common cause of pain including radicular pain. Ectopic endometrial tissue may directly affect peripheral nerves including the sciatic, which has not been modelled in animals. ⋯ Some especially painful forms of endometriosis are essentially neuropathic, because peripheral nerves are directly affected by nearby ectopic endometrial tissue. We modelled endometriosis by implanting autologous uterine tissue around rat sciatic nerve. We observed mechanical and cold pain behaviours along with signs of inflammation and nerve damage and increased pro-inflammatory cytokines at the implant site. Pain behaviours correlated with signs of nerve inflammation and damage rather than with cyst survival.
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Chronic postsurgical pain (CPSP) is an important clinic problem. It is assessed that prevalence of chronic pain extends to 30% but it is contended that there are various risk factors. We aimed to evaluate the prevalence of chronic pain after hysterectomy, risk factors of chronicity, neuropathic features of pain, and sensorial alterations at surgery area. ⋯ Neuropathic symptoms were observed in 90 patients (96.8%). Sensorial alterations as hypoesthesia and hyperesthesia were detected around abdominal scar in 18 patients (19.4%) with pinprick test. Neuropathic symptoms should not be ignored in studies evaluating CPSP and a standard methodology should be designed for studies in this topic.
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Support Care Cancer · Aug 2016
Functional vitamin B12 deficiency in advanced malignancy: implications for the management of neuropathy and neuropathic pain.
Treatment of neuropathic pain and chemotherapy-induced peripheral neuropathy (CIPN) in patients with malignancy is often unsuccessful. Functional vitamin B12 deficiency, defined by elevated levels of the B12-dependent metabolites, methylmalonic acid (MMA), and/or homocysteine, despite normal B12 values, may cause neuropathy and is associated with disorders linked to increased oxidative stress. Since both cancer and neurotoxic antineoplastic agents increase oxidative stress, a role for functional B12 deficiency in CIPN was considered. ⋯ Functional vitamin B12 deficiency is common in subjects with advanced malignancy. Further studies are needed to determine if this disorder is a risk factor for CIPN and if B12 therapy has a role in the management and/or prevention of neuropathy and neuropathic pain in this population.
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The aim of the present study was to investigate efficacy of continuous epidural block for prevent postherpetic neuralgia (PHN) progression in cases of acute herpes zoster with severe pain and also to identify predictive factors for PHN in such conditions. We retrospectively analyzed the clinical data of patients with herpes zoster who underwent continuous epidural block between March 2013 and October 2015. Time points were set as 1 month, 3 months, and 6 months after zoster onset. ⋯ The incidence of PHN is higher in zoster patients with severe pain that requires continuous epidural block compared to incidence in the general population. Advanced age and severe initial pain intensity were predictive factors of PHN development. Prolonged catheterization resulting from weak response to treatment strongly suggested progression to PHN.