| Project/Area Number |
12670700
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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 | Nippon Medical School |
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Principal Investigator |
YAMAMOTO Takeshi Nippon Medical School, 医学部, 助手 (60307949)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Naoki Nippon Medical School, 医学部, 助手 (70291721)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Cardiac β-adrenergic receptor / Intracellular signal transduction / Rapid pacing-induced heart failure / Left ventricular dP / dt / Isoproterenol / β-arrestin / β-adrenergic receptor kinase / イソプロチレノール / 高頻度高頻度ベーシング誘発心不全 |
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| Research Abstract |
To examine the function of intracellular β-adrenergic receptor signal pathway during the development of pacing-induced heart failure, hemodynamic measurements were made with nine mongrel dogs fully awake. Signaling components were also measured using a crude cardiac sarcolemmal preparation. Furthermore, we assessed the relationship between the physiologic hemodynamic parameters and the biochemical components. Three dogs were paced for 1 d, two dogs were paced for 1 wk, and two dogs were paced for 6-7 wk. The data from dogs after 1 d, 1 wk, and 6-7 wk of pacing were compared with two sham-operated dogs. Left ventricular dP/dt in response to the acute challenges to isoproterenol was significantly decreased at 1 d and was depressed further at 1 and 6-7 wk of pacing. Both the fraction of β-adrenergic receptors binding agonist with high affinity and adenylyl cyclase activity decreased after 1 d of pacing. Ryanodine receptor decreased after 1 d of pacing, but not depressed furthermore. There were no significant changes in the total β-adrenergic receptor density, and the functional activity of Gs. β-adrenergic receptor kinase and β-arrestin did not estimated because of technical failure. Blunt responsiveness to isoproterenol derived mainly from the loss of high affinity cardiac β-adrenergic receptors. High affinity β-adrenergic receptor appears to be the most crucial change in the physiological deteriorations during the initial development of heart failure.
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