2004 Fiscal Year Final Research Report Summary
The mechanism underlying the upregulation of A1R mRNA expression in non-ischemic raight ventricle by the ischemia of left ventricle
| Project/Area Number |
15590193
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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 |
General physiology
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| Research Institution | Nihon University |
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Principal Investigator |
KOKUBUN Shinichiro Nihon University, School of Medicine, Professor, 医学部, 教授 (20153520)
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| Co-Investigator(Kenkyū-buntansha) |
HIDAI Chiaki Nihon University, School of Medicine, Lecturer, 医学部, 講師 (70228732)
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| Project Period (FY) |
2003 – 2004
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| Keywords | ventricular muscle / adenosine / A1 receptor / reperfusion / preconditioning |
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| Research Abstract |
It has been suggested that adenosine A1 receptors show protective effects on cardiac muscles against the exposure to ischemia. This phenomenon is known as preconditioning. In order to clarify the role of adosine A1 receptors in preconditioning, ischemic reperfusion hearts of rat were used and the following results have been obtained. The ischemic reperfused hearts were prepared by ligating the trunk of left anterior descending artery(LAD) with silk thread. By reperfusion after ischemia the increase of A1R mRNA expression was clearly observed in the right ventricle. In order to confirm that ligation of LAD blocks the blood flow in the left ventricle but not in the right ventricle, fluorescent dye was perfused through coronary during LAD ligation, demonstrating that blood flow throughout right ventricle was well maintained during the ligation of LAD. Signal trsmission pathway of ischemic information in left ventricle to right ventricle was investigated by pharmacologically blocking autonomic nervous systems in the heart. In the presence of atropin, propranolol and phentolamine the expression of A1R mRNA in right ventricle was increased by the ligation of LAD almost similarly to that in the absence of drugs. The same experiment described in 1 was performed in isolated heart preparation perfused by Langendorff apparatus. In 37 experiments out of 40 the reliable data could not be obtained because of the appearance of ventricular fibrillation after LAD ligation of 5 min. In the rest of 3 experiments, the significant increase of the expression of mRNA was not observed in the right ventricle. However, it is difficult to conclude that in isolated hearts the increase in the expression of A1R mRNA in the right ventricle by LAD ligation was not observed, since in these three experiments ventricular extrasystoles were frequently observed in reperfusion period.
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