| Project/Area Number |
06404056
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Anesthesiology/Resuscitation studies
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
MORI Kenjiro Kyoto University, Faculty of Medicine, Department of Anesthesia, Professor, 医学研究科, 教授 (20025620)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUDA Kazuhiko Kyoto University, Faculty of Medicine, Department of Anesthesia, Assistant Profe, 医学研究科, 講師 (90199224)
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| Project Period (FY) |
1994 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥40,900,000 (Direct Cost: ¥40,900,000)
Fiscal Year 1996: ¥5,500,000 (Direct Cost: ¥5,500,000)
Fiscal Year 1995: ¥10,400,000 (Direct Cost: ¥10,400,000)
Fiscal Year 1994: ¥25,000,000 (Direct Cost: ¥25,000,000)
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| Keywords | Opioid receptor / Ligand selectivity / Ca^<2+> channel / MAP kinase / Phospholipase A2 / Tolerance / Cyclic AMP / ホスホリパーゼA2 / サイクリックAMP / カルシウムチャンネル / アデニル酸シクラーゼ |
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| Research Abstract |
The opioid receptor is pharmacologically classified into mu, delta and kappa on the basis of the difference in ligand binding affinity. To elucidate which portion of the opioid receptor molecule determines the difference in ligand binding affinity, we constructed chimeric receptors between the mu-and delta-opioid receptors, and analyzed their ligand binding properties. The results obtained suggest that the difference in binding affinity for DAGO,a mu-selective agonist, is determined by the difference in amino acid sequence of the region spanning the transmembrane segments II-III.Furthermore, analysis of the mutant receptors, in which one amino acid residue in the region spanning the transmembrane segments II-III is substututed, suggest that one amino acid difference between the mu-and delta-receptors determines the difference in DAGO binding affinity.
We transfected NG108-15 cells with the mu-opioid receptor cDNA and analyzed agonist-induced response of Ca^<2+> channels by the patch cla
… More
mp method. The results obtained indicate that activation of the mu-receptor leads to inhibition of the N-type Ca^<2+> channels through the action of pertussis toxin-sensitive G-proteins.
We expressed opioid receptors in chinese hamster ovary (CHO) cells by cDNA transfection, and analyzed opioid agonist-induced change in MAP kinase activity. Our results indicate that activation of the opioid receptors induces activation of MAP kinase, and that pertussis toxin-sensitive G-proteins and protein kinase C are involved in this response. Furthermore, we dumonstrated that opioid-induced MAP kinase activation results in activation of phospholipase A2 and arachidonic acid release.
Using CHO cells stably transfected with the mu-opioid receptor cDNA,changes in opioid receptor fuction induced by chronic agonist stimulation were analyzed. Chronic agonist stimulation induced internalization and down-regulation of the mu-receptor, and increase in cyclic AMP production by adenylate cyclase.
These results described above can be expected to contribute to understanding of the molecular basis of the opioid receptor function and elucidation of the molecular mechanism for opioid tolerance. Less
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