• Journal of Acupuncture Research
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• v.23 no.5
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• pp.23-29
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• 2006

Objectives : The present study was conducted to evaluate the effects of automatically controlled rotating acupuncture (ACRA) on thermal allodynia in neuropathic pain rats, and to examine whether the endogenous opioid system mediates the effects of ACRA. Methods : For the neuropathic surgery, the right superior caudal trunk was resected at the level between S1 and S2 spinal nerves innervating the tail. Two weeks after the nerve injury, ACRA stimulation with 4 different stimulation conditions (i.e., angle and frequency of rotation: 90o+1Hz, 90o+1/4Hz, 360o+/1Hz, and 360o+1/4Hz) was delivered to the Zusanli (ST36) acupoint for 15 min. The behavioral signs of thermal allodynia were evaluated by the tail immersion test (i.e., immersing the tail in cold $(4^{\circ}C)$ or warm $(4^{\circ}C)$ water and measuring the latency to an abrupt tail movement) before and after the stimulation. In an additional set of experiments, we examined the effects of naloxone (opioid Results : ACRA stimulations under all of the conditions above significantly relieved thermal antagonist, 2mg/kg, i.p.) on the action of ACRA stimulation. allodynia. There is no difference in the anti-allodynic effects among the 4 stimulation conditions. In addition, the effect of ACRA on thermal allodynia was reversed by naloxone pretreatment. Conclusion : These results indicate that ACRA stimulations have relieving effects on thermal allodynia in neuropathic pain rats, irrespective of stimulation parameters, and that this is mediated by the endogenous opioid system.

• The Korean Journal of Pain
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• v.14 no.1
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• pp.123-125
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• 2001

A 50-year-old female patient developed severe right neck and upper extremity pain, hyperesthesia and allodynia during cervical epidural block. Her pain was diagnosed as neuropathic nature. She was treated with repeated stellate ganglion block (SGB) and electrical stimulation (EST). After 3 weeks of treatment, symptomatic relief was achieved, but a mild degree of hyperesthesia and motor weakness was remained. However, she refused all treatment. So treatment was stopped. In a follow-up done, 15 weeks after the nerve injury, she had recovered without complications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.123-128
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• 2016

The study was conducted to confirm the analgesic effects of the Carbenoxolone(CBX)and P2X receptor antagonist(iso-PPADS), which separates the gap junction in the facial neuropathic pain model. The experiment used white male Sprague-Dawley rats (240~280g). The second left molars on the lower jaw was extracted to induce facial neuropathic pain, and small dental implants were implanted to induce damage to the inferior alveolar nerve. When CBX was injected twice daily to the abdominal cavity, a significant analgesic effect at 5ug/kg was observed(p<0.05). In addition, when iso-PPADS was injected twice daily into the abdominal cavity, a significant analgesic reaction was observed at $25{\mu}g/kg$(p<0.05). When the two drugs were injected together at a low concentration, in which they did not display an effect, they displayed a significant analgesic reaction at CBX 1ug/kg and iso-PPADS 2.5ug/kg(p<0.05). When a gap injunction block using a low concentration of CBX and a low concentration P2X receptor antagonist was injected together, the pain suppressing effect was observed against the orofacial neuropathic pain mechanism. These results make it possible to determine that the gap junction block using CBX and the injection of the P2X receptor antagonist plays an important role in the pain management of the facial region.

• Journal of Korean Neurosurgical Society
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• v.40 no.3
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• pp.143-147
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• 2006

Objective : Brachial plexus injury can produce a intractable chronic neuropathic pain. This study was undertaken to assess the long term outcome of microsurgical dorsal root entry zonotomy[MDT]. Methods : Between October 1997 and December 2002, 21 patients received MDT because of a intractable pain resulting from brachial plexus injury. Of these, 19 patients were followed for more than 2 years. Fourteen of 19 patients were male and patient ages ranged from 22 to 69 years. Mean pain duration was 36.8 months and all patients had severe pain of $9{\sim}10$ visual analogue scale. To achieve complete destruction of abnormal dorsal horns, thermocoagulation of the posterolateral sulcus were performed and careful gluing was done to prevent postoperative adhesion and pain recurrence. Results : Of the 19 patients, 15 patients had excellent [>75% reduction in pain] and good [$51{\sim}75%$ pain relief] results in a average postoperative period of 4.1 years. One patient had a poor [less than 25% pain relief] result. Three patients were considered to have a fair result [$26{\sim}50%$ pain relief]. Postoperative complications were 2 transient ipsilateral ataxia and 1 CSF fistula that resolved without surgical revision. Conclusion : These results indicate that MDT provides excellent long-term pain relief in medically intractable chronic neuropathic pain following brachial plexus injury without significant complications.

• The Korean Journal of Pain
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• v.11 no.1
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• pp.23-29
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• 1998

Background: The present study was conducted to investigate effects of microinjection of bicuculline, GABA-A receptor antagonist, into the brain stem nuclei on the dorsal horn neuron responsiveness in rats with an experimental peripheral neuropathy. Methods: An experimental neuropathy was induced by a unilateral ligation of L5~L6 spinal nerves of rats. After 2~3 weeks after the surgery, single-unit recording was made from wide dynamic range (WDR) neurons in the spinal cord dorsal horn. Results: Responses of WDR neurons to both noxious and innocuous mechanical stimuli applied to the somatic receptive fields were enhanced on the nerve injured side. These enhanced responsiveness of WDR neurons were suppressed by microinjection of bicuculline into periaqueductal gray(PAG) or nucleus reticularis gigantocellularis(Gi). A similar suppression was also observed when morphine was microinjected into PAG or Gi. Suppressive action by Gi-bicuculline was reversed by naloxonazine, ${\mu}$-opioid receptor antagonist, microinjected into PAG whereas PAG-bicuculline induced suppression was not affected by naloxonazine injection into Gi. Gi-bicuculline induced suppression were reversed by a transection of dorsolateral funiculus(DLF) of the spinal cord. Conclusions: The results suggest that endogenous opioids, via acting on GABAergic interneurons in PAG and Gi, may be involved in the control of neuropathic pain by activating the descending inhibitory pathways that project to the spinal dorsal horn through DLF to inhibit the responsiveness of WDR neurons.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.6
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• pp.657-666
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• 2017

Paclitaxel, a chemotherapeutic drug, induces severe peripheral neuropathy. Gabapentin (GBT) is a first line agent used to treat neuropathic pain, and its effect is mediated by spinal noradrenergic and muscarinic cholinergic receptors. Electro-acupuncture (EA) is used for treating various types of pain via its action through spinal opioidergic and noradrenergic receptors. Here, we investigated whether combined treatment of these two agents could exert a synergistic effect on paclitaxel-induced cold and mechanical allodynia, which were assessed by the acetone drop test and von Frey filament assay, respectively. Significant signs of allodynia were observed after four paclitaxel injections (a cumulative dose of 8 mg/kg, i.p.). GBT (3, 30, and 100 mg/kg, i.p.) or EA (ST36, Zusanli) alone produced dose-dependent anti-allodynic effects. The medium and highest doses of GBT (30 and 100 mg/kg) provided a strong analgesic effect, but they induced motor dysfunction in Rota-rod tests. On the contrary, the lowest dose of GBT (3 mg/kg) did not induce motor weakness, but it provided a brief analgesic effect. The combination of the lowest dose of GBT and EA resulted in a greater and longer effect, without inducing motor dysfunction. This effect on mechanical allodynia was blocked by spinal opioidergic (naloxone, $20{\mu}g$), or noradrenergic (idazoxan, $10{\mu}g$) receptor antagonist, whereas on cold allodynia, only opioidergic receptor antagonist blocked the effect. In conclusion, the combination of the lowest dose of GBT and EA has a robust and enduring analgesic action against paclitaxel-induced neuropathic pain, and it should be considered as an alternative treatment method.

• Journal of Korean Neurosurgical Society
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• v.54 no.6
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• pp.501-506
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• 2013

Objective : Spinal cord stimulation (SCS) is an effective means of treatment of chronic neuropathic pain from failed back surgery syndrome (FBSS). Because the success of trial stimulation is an essential part of SCS, we investigated factors associated with success of trial stimulation. Methods : Successful trial stimulation was possible in 26 of 44 patients (63.6%) who underwent insertion of electrodes for the treatment of chronic pain from FBSS. To investigate factors associated with successful trial stimulation, patients were classified into two groups (success and failure in trial). We investigated the following factors : age, sex, predominant pain areas (axial, limb, axial combined with limbs), number of operations, duration of preoperative pain, type of electrode (cylindrical/paddle), predominant type of pain (nociceptive, neuropathic, mixed), degree of sensory loss in painful areas, presence of motor weakness, and preoperative Visual Analogue Scale. Results : There were no significant differences between the two groups in terms of age, degree of pain, number of operations, and duration of pain (p>0.05). Univariate analysis revealed that the type of electrode and presence of severe sensory deficits were significantly associated with the success of trial stimulation (p<0.05). However, the remaining variable, sex, type of pain, main location of pain, degree of pain duration, degree of sensory loss, and presence of motor weakness, were not associated with the trial success of SCS for FBSS. Conclusion : Trial stimulation with paddle leads was more successful. If severe sensory deficits occur in the painful dermatomes in FBSS, trial stimulation were less effective.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.21.1-21.5
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• 2018

Background: The purpose of this study was to evaluate the clinical outcomes of treatment of non-odontogenic atypical orofacial pain using botulinum toxin-A. Methods: This study involved seven patients (seven females, mean age 65.1 years) who had non-odontogenic orofacial pain (neuropathic pain and atypical orofacial pain) and visited the Seoul National University Bundang Hospital between 2015 and 2017. All medication therapies were preceded by botulinum toxin-A injections, followed by injections in the insignificant effects of medication therapies. Five of the seven patients received intraoral injections in the gingival vestibule or mucosa, while the remaining two received extraoral injections in the masseter and temporal muscle areas. Results: In five of the seven patients, pain after botulinum toxin-A injection was significantly reduced. Most of the patients who underwent surgery for dental implantation or facial nerve reconstruction recovered after injections. However, the pain did not disappear in two patients who reported experiencing persistent pain without any cause. Conclusions: The use of botulinum toxin-A for the treatment of non-odontogenic neuropathic orofacial pain is clinically useful. It is more effective to administer botulinum toxin-A in combination with other medications and physical therapy to improve pain.

• The Korean Journal of Pain
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• v.26 no.2
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• pp.135-141
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• 2013

Background: Although paclitaxel is a widely used chemotherapeutic agent for the treatment of solid cancers, side effects such as neuropathic pain lead to poor compliance and discontinuation of the therapy. Ethyl pyruvate (EP) is known to have analgesic effects in several pain models and may inhibit apoptosis. The present study was designed to investigate the analgesic effects of EP on mechanical allodynia and apoptosis in dorsal root ganglion (DRG) cells after paclitaxel administration. Methods: Rats were randomly divided into 3 groups: 1) a control group, which received only vehicle; 2) a paclitaxel group, which received paclitaxel; and 3) an EP group, which received EP after paclitaxel administration. Mechanical allodynia was tested before and at 7 and 14 days after final paclitaxel administration. Fourteen days after paclitaxel treatment, DRG apoptosis was determined by activated caspase-3 immunoreactivity (IR). Results: Post-treatment with EP did not significantly affect paclitaxel-induced allodynia, although it tended to slightly reduce sensitivities to mechanical stimuli after paclitaxel administration. After paclitaxel administration, an increase in caspase-3 IR in DRG cells was observed, which was co-localized with NF200-positive myelinated neurons. Post-treatment with EP decreased the paclitaxel-induced caspase-3 IR. Paclitaxel administration or post-treatment with EP did not alter the glial fibrillary acidic protein IRs in DRG cells. Conclusions: Inhibition of apoptosis in DRG neurons by EP may not be critical in paclitaxel-induced mechanical allodynia.

• Journal of Oral Medicine and Pain
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• v.44 no.1
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• pp.40-44
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• 2019

Third molar extraction, one of the important surgical treatments commonly practiced in dentistry, presents various symptoms after surgery ranging from temporary or mild symptoms to permanent or severe complications. However, oral burning pain, dysesthesia, parageusia, dry mouth, headache and pain in multiple teeth are not the common symptoms that patients often complain after dental extraction. Here, the authors report two cases who presented acute neuropathic symptoms mentioned above in the orofacial regions following third molar extraction. At the initial examination, the healing of the tooth sockets of two patients was normal. One patient was diagnosed as megaloblastic anemia associated with Vitamin $B_{12}$ deficiency and was referred to the Department of Hematology for assessing the underlying etiology of anemia. The laboratory test for the other patient revealed microcytic anemia related to iron deficiency. The patient with iron deficiency anemia was successfully treated with iron supplement. These two cases suggest that anemia, as an underlying systemic disease, may be a rare etiology explaining acute onset of peripheral neuropathy in the orofacial regions after third molar extraction and should be considered in the assessment of patients who report neuropathic symptoms after dental extraction.