2001 Fiscal Year Final Research Report Summary
Comparative neurotoxicity of drugs administered intrathecally and epidurally in rats
| Project/Area Number |
12671469
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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 Medical University |
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Principal Investigator |
HASHIMOTO Keishi Shimane Medical University, Anesthesiology, Assistant Professor, 医学部, 講師 (60252920)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAMOTO Hiroshi Shimane Medical University, Anesthesiology, Instructor, 医学部, 助手 (20297005)
SAITO Yoji Shimane Medical University, Anesthesiology, Professor, 医学部, 教授 (50162243)
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| Project Period (FY) |
2000 – 2001
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| Keywords | epidural administration / intrathecal administration / neurotoxicity / spinal cord / local anesthetics |
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| Research Abstract |
This study was designed to compared the functional and morphologic effects of local anesthetics, lidocaine administered intrathecally and epidurally in rats.
With the approval of our animal research committee, male rats were randomly divided into two groups to be implanted with an intrathecal or epidural catheter though L4-L5 vertebra into caudal direction. Every rat received saline, or 2.5 % or 10 % lidocaine intrathecally (20 μl) or epidurally (100 μl). To evaluate behavioral changes, tail flick (TF), paw pressure (PP), and motor function (MF) tests were performed for 4 hr and 4 days after drug administration, after which rats were sacrificed. Spinal cords and nerve roots were removed and processed for the light microscopic observation.
The rats epidurally administered saline (EP-S), and 2.5 % (EP-L2.5), 10 % lidocaine (EP-L10), intrathecally administered saline (IT-S), and 2.5 % lidocaine (IT-L2.5) didn't show any sensory dysfunction 4 days after injection. Four out of six rats given 10 % intrathecal lidocaine (IT-L10) incurred sensory dysfunction 4 days after injection on the TF test but not on the PP and MF tests. The nerve injury of IT-L10 treated rats was significantly higher than that of IT-S and EP-L10 treated rats. In EP-L10 treated rats, histologic changes of spinal cords were restricted to the white matter, whereas IT-L10 treated rats resulted in injury not only in the white matter but spread into the gray matter. The injury observed in IT-L10 treated rats was severer than that in EP-L10 treated rats.
Both intrathecally and epidurally administered lidocaine induced neurologic injury in a dose dependent fashion. However, sensory and histologic impairment observed after epidural lidocaine was less severe than those after intrathecal administration.
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