2005 Fiscal Year Final Research Report Summary
Research on the mechanism that induces diurnal variation of blood pressure through biological clock
| Project/Area Number |
16590686
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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 |
Circulatory organs internal medicine
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| Research Institution | Kobe University |
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Principal Investigator |
EMOTO Noriaki Kobe University, Graduate School of Medicine, Assistant Professor, 大学院・医学系研究科, 助手 (30294218)
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| Project Period (FY) |
2004 – 2005
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| Keywords | biological clock / diurnal variation of blood pressure / circadian rhythm / CRY / knockout mouse |
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| Research Abstract |
1.Molecular identification of the output genes of biological clock
We have searched the published database for the consensus sequences that have been known to be bound to clock genes (ie, E-box : CACGTG, dbp binding site : RTTATGTAAY). We selected several possible candidate genes for the output gene. We prepared RNA samples from the heart, kidney, aorta, and investigate the expression of the genes by quantitative PCR method. With these method, we are successfully isolated over 200 genes which could be the output genes regulated by biological clock. These gene products represented a wide array of cell cycle and signal transduction related genes as well as additional circadian genes and transport functions. We have identified that renal tubular NHE3, the Na(+)/H(+) exchanger critical for systemic electrolyte and acid-base homeostasis, is a clock^controlled gene regulated directly by CLOCK : BMAL1 heterodimers in kidneys.
2.Analyses on cardiovascular function of the mice that lack biological clock
To examine the role of clock interruption on blood pressure, CRY1 and CRY2 double knockout mice were created. While wild type mice had normal circadian rhythm in complete darkness, CRY double knockout mice had no discernible pattern of their circadian blood pressure variation. Heart rate spectral analysis of variability in knockout mice suggests impaired sympathetic activity may be related to diurnal variation in blood pressure. Conditional knockout mice are now being studied to determine the effects on blood pressure when peripheral clock genes are interrupted in specific tissues.
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