| Project/Area Number |
10670632
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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 | Tokyo Medical and Dental University |
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Principal Investigator |
SAKAI Tetsuro Tokyo Medical and Dental University School of Medicine, Associate Professor, 医学部, 助教授 (40153845)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Katsushige Tokyo Medical and Dental University School of Medicine, Research Associate, 医学部, 助手 (80291342)
SATO Yoko (MOMOSE Yoko) Tokyo Medical and Dental University School of Medicine, Lecturer, 大学院・医歯学総合研究科, 講師 (70251501)
HIRANO Yuji Tokyo Medical and Dental University Medical Research Institute, Associate Professor, 難治疾患研究所, 助教授 (00181181)
KAMINO Kohtaro Tokyo Medical and Dental University School of Medicine, Professor, 医学部, 教授 (40025630)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1999: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1998: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | electrical activity / circus movement / optical recording / voltage-sensitive dye / heart / arrhythmia |
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| Research Abstract |
Multiple-site optical recordings of transmembrane voltage activity, using a voltage-sensitive dye and a multi-element photodiode array, were employed to monitor the tachycardia-like excitation in the rat atrium. Atrial preparations dissected from adult rat hearts were stained with a merocyanine-rhodanine dye (NK2761), and the action potentials were recorded simultaneously from many sites. We used a bathing medium containing 2,3-butanedione monoxime (20 mM) to reduce the contraction-related light scattering. The tachycardia-like excitation with a cycle length of about 250 - 450 ms was evoked either by a train of electrical stimuli (5-20 Hz/ 1-2 sec) or regular stimuli of 0.5-1 Hz applied with bipolar electrodes. The events lasted for various time periods (10 sec - over 10 min) and often terminated spontaneously. The spread of excitation was assessed optically, and we mapped the conduction patterns of the excitatory waves. These maps indicate that the excitatory waves often propagated in a quasi-circular pathway which often surrounded the ostium of the superior vena cava. However, several other patterns, such as "blocked areas" without anatomical obstacle, ectopic foci of pacemaking activity and more complex patterns with multiple wavefront, were also observed.
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