• The Korean Journal of Pain
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• v.22 no.1
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• pp.1-15
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• 2009

Neuropathic pain is often refractory to intervention because of the complex etiology and an incomplete understanding of the mechanisms behind this type of pain. Glial cells, specifically microglia and astrocytes, are powerful modulators of pain and new targets of drug development for neuropathic pain. Glial activation could be the driving force behind chronic pain, maintaining the noxious signal transmission even after the original injury has healed. Glia express chemokine, purinergic, toll-like, glutaminergic and other receptors that enable them to respond to neural signals, and they can modulate neuronal synaptic function and neuronal excitability. Nerve injury upregulates multiple receptors in spinal microglia and astrocytes. Microglia influence neuronal communication by producing inflammatory products at the synapse, as do astrocytes because they completely encapsulate synapses and are in close contact with neuronal somas through gap junctions. Glia are the main source of inflammatory mediators in the central nervous system. New therapeutic strategies for neuropathic pain are emerging such as targeting the glial cells, novel pharmacologic approaches and gene therapy. Drugs targeting microglia and astrocytes, cytokine production, and neural structures including dorsal root ganglion are now under study, as is gene therapy. Isoform-specific inhibition will minimize the side effects produced by blocking all glia with a general inhibitor. Enhancing the anti-inflammatory cytokines could prove more beneficial than administering proinflammatory cytokine antagonists that block glial activation systemically. Research on therapeutic gene transfer to the central nervous system is underway, although obstacles prevent immediate clinical application.

• Journal of Hospice and Palliative Care
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• v.1 no.1
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• pp.65-68
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• 1998

The neuropathic pains are not well controlled by common analgesics and opioid drugs in terminal cancer patients. The types of these pains are divided within the two cages, one is due to continuous central sensitization and the other is due to paroxymal peripheral sensitization. The mechanism of continuous central sensitization is the activity of dorsal horn neurones that are activated by C-fiber input. The tricyclic antidepressants, non-tricyclic antidepressants, and oral local anaesthesia probably produce analgesic effects in neuropathic pains through suppression of this activity. The mechanism of paroxymal peripheral sensitization is the hyper-excitability of peripheral neurones. The neuropathic pains due to peripheral sensitization respond relatively the anticonvulsants and baclofen that stabilize membranes and suppress paroxymal electrical discharge. The patients was a 38-year-old female who complained of hyperthemia on upper right extremity. The symptom of this patient was improved with anticonvulsant(dilantin 600mg).

• IMMUNE NETWORK
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• v.12 no.2
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• pp.41-47
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• 2012

Contemporary studies illustrate that peripheral injuries activate glial components of the peripheral and central cellular circuitry. The subsequent release of glial stressors or activating signals contributes to neuropathic pain and neuroinflammation. Recent studies document the importance of glia in the development and persistence of neuropathic pain and neuroinflammation as a connecting link, thereby focusing attention on the glial pathology as the general underlying factor in essentially all age-related neurodegenerative diseases. There is wide agreement that excessive glial activation is a key process in nervous system disorders involving the release of strong pro-inflammatory cytokines, which can trigger worsening of multiple disease states. This review will briefly discuss the recent findings that have shed light on the molecular and cellular mechanisms of glia as a connecting link between neuropathic pain and neuroinflammation.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.2
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• pp.183-190
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• 2010

Objectives : This study was designed to evaluate clinical effects of Hua-Tuo-Jia-Ji-Xue acupuncture treatment to neuropathic pain of patients with spinal cord injury. Methods : The clinical study was carried out 5 cases with spinal cord injury, who had been treated from December, 2008 to November, 2009 in the department of oriental rehabilitation medicine, Dong-Guk university oriental medical hospital. Results : After treating Hua-Tuo-Jia-Ji-Xue acupuncture, we find out that the VAS(Visual Analog Scale) score was significantly improved after treatment. Conclusions : These result suggest that Hua-Tuo-Jia-Ji-Xue acupuncture were effective to neuropathic pain of spinal cord injury patients.

• Journal of Korean Neurosurgical Society
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• v.38 no.3
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• pp.234-237
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• 2005

The neuropathic pain caused by lumbosacral plexopathy as a sequela to extensive pelvic and sacral fractures is rare because many posttraumatic cases remain undiagnosed as a result of the high mortality associated with these types of injury and because of the survivors of multiple trauma, including pelvic fractures, frequently have an incomplete work-up. Although surgical treatments for medically refractory lumbosacral plexus avulsion pain have been reported, an effective surgical technique for pain relief in lumbosacral plexopathy has not been well documented. We describe the effectiveness of spinal cord stimulation [SCS] in a patient suffering from severe neuropathic pain caused by lumbosacral plexopathy after an extensive pelvic fracture.

• Journal of Oral Medicine and Pain
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• v.36 no.2
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• pp.139-146
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• 2011

Neuropathic pain is defined by "pain is initiated or caused by primary lesion or dysfunction in the nervous system" and several etiologic conditions can induce the neuropathic pains. Various groups of drugs are used to treat the neuropathic pains. Not depending on anecdotal case or habitual choice, to obtain the more effective pharmacotherapy, relative-comparison index is suggested through multiple analyses of clinical trials. Depending on relative-comparison index, first-line medications and second-line medications for neuropathic pain are recommended. To support the Quality of life in patients, selection of medication is made on such recommendations.

• The Korean Journal of Pain
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• v.9 no.2
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• pp.318-325
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• 1996

Background: Sympathectomy relieves pain in sympathectically maintained pain, and subcutaneous injection of norepinephrine(NE) can rekindle mechanical allodynia. However, the mechanism of rekindling is not clear. The purpose of this study is to investigate which subtype of $\alpha$-adrenoceptor is involved in NE-induced rekindling of mechanical allodynia in sympathectomized neuropathic rats. Methods: Neuropathic injury was produced by tightly ligating the left L5 and L6 spinal nerves of 36 male Sprague-Dawley rats and bilateral lumbar sympathectomy was done at two weeks postoperatively. Starting at 7 days after sympathectomy, rekindling of mechanical allodynia was induced by NE and clonidine injected into the left paw, which was reversed by pretreatment of phentolamine and idazoxan. Mechanical allocynia was quantified by measuring the frequency of foot lifts to two von Frey filaments applied to the paw. Results: All tested rats displayed well-developed signs of mechanical allodynia at the left paw that were abolished by a bilateral lumbar sympathectomy. Subcutaneous (s.c.) injection of NE (0.05 ${\mu}g$) into the affected paw of sympathectomized neuropathic rats rekindled previous mechanical allodynia. These effects could be mimicked by an ${\alpha}_2$-receptor agonist clonidine, but not by an ${\alpha}_1$-receptor agonist phenylephrine. The NE-induced rekindling of mechanical allodynia was significantly reduced by prior s.c. injection of a mixed $\alpha$-receptor antagonist phentolamine (20${\mu}g$) and ${\alpha}_2$-receptor antagonist idazoxan(20${\mu}g$), but not by a ${\alpha}_1$-receptor antagonist terazosin (20${\mu}g$). The pretreatment of idazoxan produced dose-related inhibition of NE-induced rekindling of mechanical allodynia. The rekindling induced by ${\alpha}_2$-receptor agonist clonidine (5${\mu}g$) was also reversed by prior s.c. injection of ${\alpha}_2$-receptor antagonist idazoxan (20${\mu}g$). Conclusion: Subcutaneous injection of NE into the paw of sympathectomized neuropathic rats rekindles mechanical allodynia, which is reversed by an ${\alpha}_2$-, but not by an ${\alpha}_1$-receptor antagonist. Therefore, rekindling of mechanical allodynia in sympathectomized neuropathic rats is mediated by ${\alpha}_2$-adrenoceptor.

• The Korean Journal of Pain
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• v.14 no.1
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• pp.98-103
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• 2001

Neuropathic pain originating from multiple condition of nerve cell injury is common, but is difficult to treat. Even though many drugs such as anti-convulsants, anti-depressants, NSAIDs, opioids have been used, their clinical analgesic action were not satisfactory due to occur severe side effects. Gabapentin was introduced in 1994 as a novel antiepileptic drug and has been used to treat partial seizure. After 1995 gabapentin treatment for reflex sympathetic dystrophy (RSD) started, 45% of the reports about the analgesic efficacy of gabapentin were restricted to the treatments of non-epileptic pain syndrome. This drug is preferred to treat neuropathic pain because of a lower incidence of its side effects than those of other anti-convulsants and anti-depressants. For evaluating it's analgesic efficacy, the changes in the patients' subjective pain intensity was measured by the score on the visual analogue scale (VAS) and patient's objective pain intensity by measuring the skin temperature via infrared thermography were investigated respectively. Side effects of gabapentin were look into. We observed successful relief of neuropathic pain in the three patients which included post-herpetic neuraligia, complex regional pain syndrome (CRPS) and diabetic neuropathic pain, and the side effects of gabapentin were at acceptable levels.

• The Korean Journal of Pain
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• v.23 no.3
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• pp.172-178
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• 2010

Background: Tumor necrosis factor-alpha and other proinflammatory cytokines are becoming well recognized as key mediators in the pathogenesis of many types of neuropathic pain. Thalidomide has profound immunomodulatory actions in addition to their originally intended pharmacological actions. There has been debate on the analgesic efficacy of opioids in neuropathic pain. The aim of this study was to investigate the effect of thalidomide and morphine on a spinal nerve ligation model in rats. Methods: Male Sprague-Dawley rats weighing 100-120 g were used. Lumbar (L) 5 and 6 spinal nerve ligations were performed to induce neuropathic pain. For assessment of mechanical allodynia, mechanical stimulus using von Frey filament was applied to the paw to measure withdrawal threshold. The effects of intraperitoneal thalidomide (6.25, 12.5, 25 and 50 mg/kg, respectively) and morphine (3 and 10 mg/kg, respectively) were examined on a withdrawal threshold evoked by spinal nerve ligation. Results: After L5 and 6 spinal nerve ligation, paw withdrawal thresholds on the ipsilateral side were significantly decreased compared with pre-operative baseline and with those in the sham-operated group. Intraperitoneal thalidomide and morphine significantly increased the paw withdrawal threshold compared to controls and produced dose-responsiveness. Conclusions: Systemic thalidomide and morphine have antiallodynic effect on neuropathic pain induced by spinal nerve ligation in rat. These results suggest that morphine and thalidomide may be alternative therapeutic approaches for neuropathic pain.

• Korean Journal of Psychosomatic Medicine
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• v.7 no.2
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• pp.274-280
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• 1999

A variety of mechanism may generate pain resulting from injury to the central and peripheral nervous system. None of these mechanism is disease-specific, and several different pain mechanism may be simultaneously present in anyone patient, independent of diagnosis. Diagnosis of neuropathic pain is often easily made from information gathered on neurologic examination and from patient history. Although treatment of neuropathic pain may be difficult, optimum treatment can be achieved if the neurologist has a complete understanding of therapeutic options, the mainstay of which is pharmacotherapy. Selection of an appropriate rharmacologic agent is by trial and error since individual responses to different agents, doses, and serum levels are highly variable. An adequate trial for each agent tried is key to pharmacologic treatment of neuropathic pain. Tricyclic antidepressants are first-line agents, although other drugs, including anticonvulsants, local anesthetic antiarrhythmics, clonidine, opiates, and certain topical agents, also offer pain relief in some patient populations. The novel antidepressants venlafaxine and nefazodone are potentially useful new drugs that are better tolerated than tricyclic antidepressants. Also Gabapentine seems an interesting and promising drug for the treatment of neuropathic pain.