| Project/Area Number |
63570406
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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 | National Institute of Fitness and Sports in Kanoya (1989)
Kagoshima University (1988) |
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Principal Investigator |
SAITOU Kazuto National Institute of Fitness and Sports in Kanoya Associate Professor, 体育学部, 助教授 (50170494)
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| Co-Investigator(Kenkyū-buntansha) |
加計 正文 鹿児島大学, 医学部, 助手 (90214270)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1989: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1988: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Angiotensin II / NeuropeptideY / Atrial natriuretic peptide / conduction system / rat / オートレジオグラフィー / アンキオテンシンII / ニューロペプタイド |
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| Research Abstract |
We investigated binding sites of atrial natriuretic factor (ANF), neuropeptide Y (NPY) and angiotensin II (ANG) in the conduction system of the rat heart by the autoradiography in combination with computerized microdensitometry. Each tissue section (16mum in thick) containing sinoatrial node and atrioventricular(AV) node was incubated with 125 I-ANF, 125 I-NPY and 125 I-Sar^1-ANGII to generate autor-adiograms that were compared with other audiograms from 125 I-labeled standards. We were not able to find any binding site of ANF and NPY in sinoatrial node and AV node. However ANG II binding sites were highly localized in both sinoatrial and AV nodes. High number of ANG II binding sites were present in both sinoatrial and AV node (28.6<plus-minus>5.9 and 72.2<plus-minus>6.8 from/mg protein in each : n=6, mean S. E.). Low number of ANG II binding sites were present both in interventricular septum and right atrium (less than 10 fmol/mg protein). Sar^1-ANG II (1nM) increased heart rate in isolated hearts perfused with 3mM HEPES buffer (ph7.4), an effect not influenced by 1muM (-) propranolol.
Our results suggest that ANGII have direct chronotropic effect through stimulation of specific receptors in the conduction system of the heart, but ANF and NPY may not.
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