1992 Fiscal Year Final Research Report Summary
MODULATION OF DENTAL PAIN BY ENDOGENOUS PEPTIDES
| Project/Area Number |
02454426
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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 |
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) |
1990 – 1992
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| Keywords | Enkephalin / Substance P / Dental Pulp / Calcium Channel / Morphine / Serotonin / Trigeminal Sensory Nuclear |
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| Research Abstract |
Distibution of various peptides throughout the central nervous system has been shown. Among of them. substance P is most abundantly concentrated in primary afferent terminals and is involved in pain transduction. Enkephalins have also been suggested to modulate pain transduction. In the present study, we investigate the physiological significance of these peptides in modulating dental pain.
1) Processing of enkephalins from precursor proteins was studied in dental pulp. Precursor proteins of enkephalins were extracted in acidic solution from dental pulp homogenate and applied on Sephadex G-100 column. Proteins producing enkephalins by digestion were eluted with molecular weight approximately 58,000. It was found that enkephalin producing enzymes are concentrated in lysosomal fraction. Purification through CM Sephadex C-50 column yielded 23.6kDa protein having cathepsin B activity. This protein appeared to be enkephalin producing enzyme(s). Production of enkephalin in cultured fibroblasts of rat dental pulp was also observed.
2) Regulation of calcium channels by morphine in trigeminal ganglion was investigated. Although both L- and N-type calcium channels distribute in trigeminal ganglion, only the latter was shown to be regulated by morphine.
3) Perfusion of superficial layers of the subnucleus caudalis of the trigeminal sensory nuclear complex with push-pull cannula induced the release of substance P and serotonin following tooth pulp stimulation. Morphine enhanced the release of serotonin and reduced that of substance P. Stimulation of raphe nucleus or local administration of serotonin also inhibited the release of substance P. It was suggested that descending serotonergic systems modulated the pain transduction.
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Research Products
(20 results)
