1993 Fiscal Year Final Research Report Summary
Culture method of human renal collecting duct cells and identification of alpha 2 adrenergic receptor
| Project/Area Number |
04670549
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | Yokohama City University |
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Principal Investigator |
YASUDA Gen Yokohama City University, School of Medicine, the Second Department of Medicine, Lecturer, 医学部・第2内科, 講師 (10145675)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Adrenergic alpha2 receptor / Papillary collecting duct / Rauwolscine / Prazosin / Oxymetazoline / オキシメタゾリン |
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| Research Abstract |
The epithelial cells prepared from human kidney papillary collecting ducts did not grow easily. Repeated passage of cultured cells revealed different cell type from original cells, showing many fibroblasts. As a result, we failed to obtain cultured cells enough to carry out the assigned examinations including radioligand binding assay, cAMP assay and northern blot analysis. Instead, we were able to characterize the adrenergic alpha 2 receptor subtype, alpha 2A, in both renal medulla and cortex, using fresh human kidneys. [3H] rauwolscine, a specific adrenergic alpha 2 receptor antagonist, binding to crude membrane provided from human kidney medulla and cortex (number=8) was rapid, saturable and reversible with phentolamine. The Ki of l-epinephrine was ten times higher than d-epinephrine, suggesting that the binding was stereo specific. The rank order of potency to displace [3H] ligand was rauwolscine, yohimbine, WB4101, BAM 1303, oxymetazoline, SKF104078, prazosin and corynanthine for both renal medulla and cortex. The kd and Bmax were 5.6 nM and 33.4 fmol/mg protein for cortex and 5.1 nM and 63 fmol/mg protein for medulla. These results indicate that both human renal medulla and cortex have adrenergic alpha 2A receptor. Our results do not consist with those reported by other investigators using the molecular cloning method, in which alpha 2C adrenergic receptor is predominant in human kidney. One of the reasons for this discrepancy is the difference in methodology for demonstrating alpha 2 receptor subtype. This interpretation awaits further demonstration.
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