1989 Fiscal Year Final Research Report Summary
COMPREHENSIVE STUDIES ON THE TRANSDUCTION AND MODULATION OF DENTAL PAIN IN THE CENTRAL NERVOUS SYSTEM AND IN THE PERIPHERY.
| Project/Area Number |
61440078
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | OSAKA UNIVERSITY |
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Principal Investigator |
INOKI Reizo OSAKA UNIVERSITY FACULTY OF DENTISTRY, PHARMACOLOGY PROFESSOR, 歯学部, 教授 (60028719)
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| Co-Investigator(Kenkyū-buntansha) |
MAEDA Sadaaki OSAKA UNIVERSITY FACULTY OF DENTISTRY, PHARMACOLOGY RESEARCH ASSISTANT, 歯学部, 助手 (00135732)
YONEHARA Norifumi OSAKA UNIVERSITY FACULTY OF DENTISTRY, PHARMACOLOGY RESEARCH ASSISTANT, 歯学部, 助手 (70124534)
KUDO Teruo OSAKA UNIVERSITY FACULTY OF DENTISTRY, PHARMACOLOGY ASSISTANT PROFESSOR, 歯学部, 講師 (10028805)
SAITO Kihachi OSAKA UNIVERSITY FACULTY OF DENTISTRY, PHARMACOLOGY ASSOCIATE PROFESSOR, 歯学部, 助教授 (40110788)
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| Project Period (FY) |
1986 – 1989
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| Keywords | Dental pain / Methionine enkephalin / Bradykinin / Leucine enkephalin / Substance P / Dental pain / Trigeminal ganglion / Trigeminal nucleus caudalis |
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| Research Abstract |
Mechanisms of perception, transduction and modulation of dental pain in the central nervous system and in the periphery were studied with special interests in peptides. Those studies were conducted in dental pulp, trigeninal ganglion and trigeminal nucleus caudalis.
1) Production of methionine enkephalin by noxious stimuli in dental pulp We first reported the existence of methionine enkephalin in dental pulp. Extensive studies on the production of methionine enkephalin in dental pulp have revealed the following observations. Noxious stmuli to dental pulp enhanced the formation of bradykinin which, in tern, activates the enkephalin processing enzyme. This increase of enkephalin has been suggested to be engaged in the modulation of pain. The enzyme has molecular weight of 23.6K and locates in lysosome. Precursor protein for enkephalin distributes in microsomal and supernatant fractions having a molecular weight of 58K.
2) Leucine enkephalin in trigeminal ganglion Immunocytochemical studies demonstrated leucine enkephalin containing neurons in guinea pig trigeminal ganglion. It was found that leucine enkephalin in trigeninal ganglion affect calcium channels by lowering the affinity for calcium.
3) Release of substance P and methionine enkephalin in trigeninal nucleus caudalis. Electrical stimulation of rabbit dental pulp caused the release of substance P, methionine enkephalin and serotonin in trigeminal nucleus caudalis. It was found that the release of substance P was inhibited by opioids and serotonin. Thus, it was suggested that substance P is transmitter involved in nociception in trigeminal nucleus caudalis and its release is modulated by enkephalin and serotonin.
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