2003 Fiscal Year Final Research Report Summary
Central nervous system modulates pain induced by orthodontic tooth movement
| Project/Area Number |
14571948
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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 |
矯正・小児・社会系歯学
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
YAMASHIRO Takashi OKAYAMA UNIVERSITY, Graduate School of Medicine and Dentistry, Associate Professor, 大学院・医歯学総合研究科, 助教授 (70294428)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAMOTO Manabu Okayama University, Graduate School of Medicine and Dentistry, Assistant Professor, 大学院・医歯学総合研究科, 助手 (40252978)
YAMAMOTO Teruko (TAKANO Teruko) Okayama University, Graduate School of Medicine and Dentistry, Professor, 大学院・医歯学総合研究科, 教授 (00127250)
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| Project Period (FY) |
2002 – 2003
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| Keywords | tooth movement / pain / modulation / opioid peptide / enkephalin / serotonergic / inhibitory system / antinociception |
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| Research Abstract |
Orthodontic tooth movement causes pain and discomfort to patients. Pain information is transmitted via an ascending pain pathway from the peripheral tissues to the central nervous system. In addition, there is also a descending pathway that allows the brain to modulate pain sensation. Endogenous pain control system involves multiple pathways, and multiple endogenous opioid peptides are released in both spinal and supraspinal levels and produce analgesia. However it is not clearly whether experimental tooth movement activates endogenous enkephalinergic system. To investigate the possible involvement of this system during experimental tooth movement, we analyzed possible deviation of Preproenkephalin (PPE) mRNA expression pattern by using in situ hybridization.
In this study, the experimental tooth movement upregulates PPE mRNA only in the dorsomedial part of the superficial layer of Vc. Furthermore, this upregulation of the expression was confirmed only in the ipsilateral side in contrast to that of control rats. The resent findings together with previous ones showed that endogenous enkephalinergic systems were activated presumably by the nociception caused by the experimental tooth movement. Nociceptive somatic stimuli also activate descending monoaminergic pathways, which modulate the transmission of ascending sensory messages, and monoaminergic neurons projecting to the dorsal spinal cord are critical to the regulation of transmission of nociceptive information. It is known that nociception induced by experimental tooth movement activates the endogenous descending serotonergic system Recent study showed S-HT up regulates the PPE mRNA expression in the cultured spinal cord. Taken, together, in the antinociception mechanism during experimental tooth movement, serotonergic descending systems exert their inhibitory roles by activating the PPE gene and c-fos is associated with this serotonergic regulation of that endogenous opioid ligand genes.
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