| Project/Area Number |
60450018
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Psychology
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| Research Institution | Osaka City University |
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Principal Investigator |
UMEMOTO Mamoru Faculty of Letters, Osaka City Univiersity, 文学部, 教授 (60101284)
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| Project Period (FY) |
1985 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1985: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | Stress-induced alalgesia / Hot-plate method / Morphine / ラット / ストレス / 鎮痛 / オピオイド / 熱板法 |
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| Research Abstract |
Rat pups were daily given footshock, just putting in a footshock apparatus or no handling from birth to twenty-one days of age. They were reared with on manipulation afterwards. After maturation, they were assesed for hot-plate paw-licking latency, morphine induced analgesia and opioid receptor binding assaya. In footshocked animals, a significant increase was found in paw-licking latency and in antinociceptive dffect of morphine(1.25, 2.5, and 5.0 mg-kg) compared with other two controls. The analgesic effect of morphine was antagonized with pretreatment of naloxone(2.0 mg/kg). No significant difference was found in binding assay( Bmax and kd for both ( Inaloxone and ( ) D-ala,D-leu-enkephalin between three groups). These results suggest thatexposure to footshock in preweanling perios has the long term effecton the sensitivity of rats to painful event, decreasing the pain sensitivity, probably through chronic fundtional changes in endogeneous opiod systemat presynaptic level rather than in postsynaptic opioid receptor activity.
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