2003 Fiscal Year Final Research Report Summary
A study of effects of morphine tolerance on spinal cord in the rat incisional pain model
| Project/Area Number |
14571435
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Anesthesiology/Resuscitation studies
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| Research Institution | SHIMANE UNIVERSITY FACULTY OF MEDICINE (2003)
Shimane Medical University (2002) |
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Principal Investigator |
KOSHIZAKI Masayuki SHIMANE UNIVERSITY, FACULTY OF MEDICINE, ASISTANT, 医学部, 助手 (40294376)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Yoji SHIMANE UNIVERSITY, FACULTY OF MEDICINE, PROFESSOR, 医学部, 教授 (50162243)
DOI katsushi SHIMANE UNIVERSITY, FACULTY OF MEDICINE, ASSOCIATE PROFESSOR, 医学部, 助教授 (20304272)
KIRIHARA Yumiko SHIMANE UNIVERSITY, FACULTY OF MEDICINE, TECHNICIAN, 医学部, 教務職員 (90234400)
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| Project Period (FY) |
2002 – 2003
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| Keywords | post-operative pain / morphine tolerance / spinal dorsal horn |
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| Research Abstract |
We made morphine tolerated model rats with placing the catheter in the sub-dural space and administered morphine. In control group, saline was administered. After five-day administration of morphine, rats showed morphine tolerance in the behavioral test. Using these rats, electrophysiological experiments were performed. A laminectomy was performed and tungsten microelectrodes were advanced in the spinal dorsal horn to isolate the activity of a single dorsal horn neuron. When the extracellular activity of a single dorsal horn neuron was isolated, receptive field was determined and marked on the shaved skin. And unit activity of the neuron for noxious stimuli was collected and analyzed. After that, an incision was made through the skin and fascia of the receptive field, and then the incision was sutured to make a post-operative pain model. After surgery, receptive field was re-determined and marked on the shaved skin. And unit activity of the neuron for noxious stimuli was collected and analyzed again. To date, the number of the neurons from, which the data was collected was still small and the statistical analysis could not show the difference between morphine tolerated group and control group. So the next experiment (comparison of the dorsal horn neuronal activity of two groups when administered morphine) has not started. We have not come to the point that we prove our hypothesis that hyperalgesia may influenced in the process of formation of morphine tolerance.
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