| Project/Area Number |
09671888
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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 |
Functional basic dentistry
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
SAHARA Yoshinori Dept Phyiology, Fact Dentistry, Tokyo Medical and Dental University, Assistant Professor, 歯学部, 講師 (40206008)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Yoshio Dept Phyiology, Fact Dentistry, Tokyo Medical and Dental University, Professor, 歯学部, 教授 (10010026)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Trigeminal ganglion neurons / Agonist / Metabotropic glutamate receptors / Glutamate receptor subunit / Kainate receptors / AMPA receptors / NMDA receptors / グルタミン酸レセプター / 三叉神経節 / カイニン酸型受容体 / 味細胞 / メタボトロピック型受容体 |
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| Research Abstract |
In order to search for functional role of glutamate receptors in the peripheral system, we examined the distribution of glutamate receptor subunits. In the trigeminal ganglion (TG), all the AMPA (GluR1-4) and kainate (GluR5-7, KA1-2) receptor subunits were detected by RT-PCR.Patch-clamp recordings from TG neurons demonstrated that only small neurons (<20 mum in diameter) responded to L-glutamate and that physiological and pharmacological features of the response is identical to those of the heteromeric GluR5/KA-2 combination (Sahara et al. 1997). We further studied how many agonists are necessary to activate ionotropic glutamate receptors, and found that the AMPA receptor channel can be opened through two agonists binding steps (Clements et al. 1998). It suggests a possibility of negative cooperation among the receptor subunits, while exact stoichiometry of the glutamate receptor remains to be known. In the tongue and olfactory bulb, cellular and F subcellular localization of mGluRs (mGluRl-7) were investigated by using affinity purified polyclonal antibodies directed to their predicted C-terminus. mGluR 4 immunoreactivity was detected in taste buds at light microscopic level, however, electron microscopic observation revealed that the mGlaR 4-immunoreactivity were not localized in the cell membrane, suggesting that mGluR4 would neither be an "umaini" receptor itself, nor be involved in the synaptic transmission. Antibodies against mGluR1alpha, 2/3, 5a and 7a selectively stained different elements in the olfactory bulb. Physiological studies using slice patch recordings also revealed that NMDA receptors play an crucial role at dendrodendritic reciprocal synapses between mitral and granule cells (Schoppa et al. 1998), which presents striking contrast to any central synapses where AMPA receptors relay the electrical signals and NMDA receptors serve a modulatory function.
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