| Co-Investigator(Kenkyū-buntansha) |
SAITO Shigeru Gunma University, Dept Anesthesiology, Associate, 医学部, 助手 (40251110)
ISHIZAKI Keiji Gunma University, Dept Anesthesiology, Assistant Prof, 医学部, 講師 (50193305)
INOUE Tomio Gunma University, Dept Nuclear Med, Associate Prof, 医学部, 助教授 (80134295)
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| Research Abstract |
Several neuropathic pain models which induced by lumbar spinal nerve ligation have been reported, however, the neuropathic pain frequently observed following thoracic surgery. In this research program, we have established a novel animal (rat) model of the post-thoracotomy pain syndrome. In the rats, inter-costal nerve damage provoked neuropathic pain, however, inter-costal bone fracture without nerve damage did not induce the pain. Increase in NK-1 receptor was observed combined with the manifestation of neuropathic pain showing the peak at the second week after the surgery. In the sciatic nerve ligation rat, 5-HT2 receptor agonists had an anti- allodynic action, but not other 5-HT agonists did not.
Positron emission tomography (PET) method was used to image regional brain activity in patients with unilateral chronic pain. Scans of the patient disclosed a remarkable increase of regional blood flow and metabolic rate of oxygen in the thalamus receiving inputs from the painful area, but the thalamic blood flow decreased to the contralateral level after the successful pain treatment.
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