| Project/Area Number |
17590201
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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 |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Nagoya University |
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Principal Investigator |
SATO Jun Nagoya University, RESEARCH INSTITUTJ E OF ENVIRONMENTAL MEDICINE, ASSOCIATE PROFESSOR (00235350)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,640,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥240,000)
Fiscal Year 2007: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | chronic pain / weather / atmospheric pressure / vestibular nerve nucleus / 除脳 / 疼痛 / 自律神経 / 動物モデル |
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| Research Abstract |
1.We tested whether lowering barometric pressure at slower rates influences neuropathic pain in rats. Mechanical hyperalgesia was evaluated by counting the number of foot withdrawals to stimulation with von Frey filaments that were applied ten times to the plantar skin. More than 5 hPa/h and 10 hPa/h of decompression rate and decompression > 5 hPa and > 10 hPa from the atmospheric pressure augmented pain-related behaviors in SNL (L5 spinal nerve ligated) and CCI (sciatic nerve loose ligated) rats, respectively.
2.Effects of LP (27 hPa over 8 min) and LT (7℃ lower than 22℃) on autonomic parameters in conscious rats were tested. Systemic blood pressure (BP) and heart rate (HR) were telemetrically recorded. Pulse interval variability was also analyzed ; the low- (LF) and high- frequency (HF) power and LF/HF ratio, an index of relative sympathetic activity, were measured. The BP increased in the middle of the LP-exposure period. The HR and LF/HF ratio were clearly increased in the early part of the LP-exposure period. In the LT exposure, the BP and HR were gradually increased to the peak values in the late part of the exposure period, while LF/HF ratio was increased throughout the exposure period. These results indicate that the LP and LT exposures increased the BP and HR with different time courses. The increase in the LF/HF ratio during both LP and LT exposures indicates that both environments induce sympathetic> parasympathetic activation.
3.We hypothesized that sympathetic nerve activity plays a role in pain-aggravation under LP. Therefore, we directly recorded lumbar sympathetic nerve activity in decerebrated-galaminized rats and examined its change by LP. BP and HR were significantly increased by LP.
4.We recorded unit activity from the vestibular nerve nucleus of anesthetized rat. About 30% of the recorded units was activated by the LP exposure
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