• The Korean Journal of Pain
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• v.8 no.1
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• pp.18-24
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• 1995

We produced the causalgiform pain by the tight ligation of L5 and L6 spinal nerves in the adult rats. To evalute the effect of Ketamine -noncompetitive NMDA (N-methyl-D aspartate) antagoinst- on the causalgiform pain, we tested the changes of; withdrawal sensitivity to the innocuous mechanical stimulation of Von Frey hair 2.35 g(mechanical allodynia); withdrawal frequency to the cold stimulation of acetone (cold allodynia); and total withdrawal time (second) to the cold ($4^{\circ}C$) plate stimulation (cold hyperalgesia) after the administration of 1 mg, 3 mg, 10 mg/kg ketamine. The results were as follows: 1) Cold hyperalgesia was significantly reduced (p<0.05) by 1 mg, 3mg, 01 mg/kg ketamine. 2) Cold allodynia and mechanical allodynia was significantly reduced (p<0.05) by 10 mg/kg ketamine. Above results suggest a therapeutic utility of ketamine in treatment of causalgia - especially, cold hyperalgesia.

• The Korean Journal of Pain
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• v.13 no.1
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• pp.105-110
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• 2000

Central neuropathic pain may occur in 10~20% of the patients after spinal cord injury. The central pain syndrome include spontaneous continuing and intermittent pain as well as evoked pain. The pain is evoked by non-noxious stimulation of the region (allodynia) and repeated stimulation (wind-up phenomenon). Four patients were referred suffering from severe pain, allodynia and hyperaesthesia after spinal cord injury. They had received conventional treatment with non-steroidal anti-inflammatory drugs, steroid, anticonvulsant, antidepressant and rehabilitation which failed to provide pain relief. We administered combination of low doses of morphine and ketamine (10 mg) through the epidural catheter with other conventional therapy. Satisfactory pain relief was achieved in each patient. The reduction of pain was not associated with severe side effects. The most bothersome side effect of ketamine was dizziness in one patient, only caused by bolus injection (ketamine 10 mg with normal saline 10 ml). This suggests synergy from this combination that provides an alternative treatment for central pain.

• The Korean Journal of Pain
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• v.13 no.2
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• pp.251-254
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• 2000

A 20-year-old male patient developed severe right leg pain, hyperesthesia and allodynia after multiple lumbar epidural blocks. His pain was neuropathic pain (complex regional pain syndrome type I). The patient was treated with repeated administration of epidural ketamine at the rate of 0.2~0.7 mg/kg on multiple occasions. Complete relief of pain was achieved.

• The Korean Journal of Pain
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• v.11 no.2
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• pp.294-298
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• 1998

The feature of neuropathic pain may occur in the absence of any apparent stimulus and be exaggerated in either amplitude or duration. Peripheral nerve injury may produce neuropathic pain and opioids have been shown to be relatively unsatisfactory for the treatment of most cases of neuropathic pain. The NMDA receptor system is involved in transmission and modulation of nociceptive information. We treated patients with severe pain, hyperaesthesia and allodynia with epidural injection of NMDA receptor antagonist, ketamine (10 mg) and morphine (0.5 mg) or other opioid. The combinations provided effective pain management in 23 patients with neuropathic pain.

• The Korean Journal of Pain
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• v.20 no.2
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• pp.190-194
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• 2007

Complex regional pain syndrome (CRPS), which is a syndrome that is defined by pain and sudomotor and/or vasomotor instability, is usually resistant to conventional treatment. Here, a case involving a 30-year-old male patient with CRPS type I who showed severe intractable right shoulder pain with allodynia and hyperalgesia despite being treated with oral medications, nerve blocks including thoracic sympathetic neurolysis, and spinal cord stimulation is described. The patient frequently visited the emergency room due to severe uncontrollable breakthrough pain. Although a favorable effect was observed in response to intermittent ketamine infusion therapies that were performed on an outpatient basis, acute exacerbation of pain occurred frequently during the night and could not be controlled. Therefore, subcutaneous ketamine infusion therapy using a patient-controlled analgesic system was attempted and found to effectively control acute exacerbation of pain during 6 weeks of infusion without serious complications.

• International Journal of Oral Biology
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• v.40 no.3
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• pp.117-125
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• 2015

The present study investigated the role of central $GABA_A$ and $GABA_B$ receptors in orofacial pain in rats. Experiments were conducted on Sprague-Dawley rats weighing between 230 and 280 g. Intracisternal catheterization was performed for intracisternal injection, under ketamine anesthesia. Complete Freund's Adjuvant (CFA)-induced thermal hyperalgesia and inferior alveolar nerve injury-induced mechanical allodynia were employed as orofacial pain models. Intracisternal administration of bicuculline, a $GABA_A$ receptor antagonist, produced mechanical allodynia in naive rats, but not thermal hyperalgesia. However, CGP35348, a $GABA_B$ receptor antagonist, did not show any pain behavior in naive rats. Intracisternal administration of muscimol, a $GABA_A$ receptor agonist, attenuated the thermal hyperalgesia and mechanical allodynia in rats with CFA treatment and inferior alveolar nerve injury, respectively. On the contrary, intracisternal administration of bicuculline also attenuated the mechanical allodynia in rats with inferior alveolar nerve injury. Intracisternal administration of baclofen, a $GABA_B$ receptor agonist, attenuated the thermal hyperalgesia and mechanical allodynia in rats with CFA treatment and inferior alveolar nerve injury, respectively. In contrast to $GABA_A$ receptor antagonist, intracisternal administration of CGP35348 did not affect either the thermal hyperalgesia or mechanical allodynia. Our current findings suggest that the $GABA_A$ receptor, but not the $GABA_B$ receptor, participates in pain processing under normal conditions. Intracisternal administration of $GABA_A$ receptor antagonist, but not $GABA_B$ receptor antagonist, produces paradoxical antinociception under pain conditions. These results suggest that central GABA has differential roles in the processing of orofacial pain, and the blockade of $GABA_A$ receptor provides new therapeutic targets for the treatment of chronic pain.

• The Korean Journal of Pain
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• v.22 no.1
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• pp.107-111
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• 2009

Neuroablation should be performed cautiously because neuropathic pain can occur following denervation of a somatic nerve. A 34-year-old man presented with severe penile pain and allodynia following a selective neurectomy of the sensory nerve that innervated the glans penis for treatment of his premature ejaculation. He was treated with various nerve blocks, including continuous epidural infusion, lumbar sympathetic block and sacral selective transforaminal epidural blocks, as well as intravenous ketamine therapy. However, all of the treatments had little effect on the relief of his pain. We performed spinal cord stimulation as the next therapy. After this therapy, the patient has currently been satisfied for 3 months.