1998 Fiscal Year Final Research Report Summary
Study of the relationship between molecular structure and function in epithelial sodium channel.
| Project/Area Number |
09671173
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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 |
Kidney internal medicine
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| Research Institution | Jichi Medical School |
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Principal Investigator |
ONO Shuichi Jichi Medical School, Dept.Nephrol., Instructor, 医学部, 助手 (90285776)
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| Co-Investigator(Kenkyū-buntansha) |
MUTO Sigeaki Jichi Medical School, Dept.Nephrol., Assistant Prof., 医学部, 講師 (40190855)
KUSANO Eiji Jichi Medical School, Dept.Nephrol., Associate Prof., 医学部, 助教授 (50102249)
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| Project Period (FY) |
1997 – 1998
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| Keywords | inner medulla / inner medullary collecting duct / rat epithelial Na^+ channel / low-Na^+ diet / rENaC / Na^+ transport |
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| Research Abstract |
The' purpose of the present study was to determine whether the renal inner medulla expresses mRNA for the rat epithelial Na^+ channel (rENaC), and, if so, to define their regulatory properties using a low Na^+ diet model. We have developed a specific probe for alpha subunit using RT-PCR with rENaC c subunit specific primers. Probe for rENaC ct subunit hybridized not only to distal colon RNA but also to inner medulla RNA derived from normal diet rats. we examined the effect of low Na^+ diet on alpha, beta and gamma subunits mRNA expression of rENaC using full length cDNA as a probe. A marked elevation of rENaC ct subunit mRNA abundance in inner medulla was observed in response to high aldosterone plasma concentration induced by dietary Na^+ deprivation. On the other hand, neither beta nor gamma subunits mRNA expression was enhanced by low Na^+ diet. From these results, it is suggested that rENaC is responsible for Na^+ transport in renal inner medulla and is probably regulated via transcriptional control of the alpha subunit of ENaC.
Furthermore, we are now raising peptide-directed polyclonal antibodies to the a, beta and gamma subunits of ENaC.Immunofluorescence labeling with beta or gamma antibodies revealed apical localization in some distal tuble cells from rat kidney. Further studies will be required to evaluate the specificity of antibodies for beta or gamma subunits of ENaC.The relationship between molecular structure and function will be studied.
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