1989 Fiscal Year Final Research Report Summary
Quantitative analysis of the electrogenic ion exchange current using the cell dialysis method in the isolated cardiac myocytes.
| Project/Area Number |
63480106
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Neurophysiology and muscle physiology
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| Research Institution | Kyushu University |
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Principal Investigator |
NOMA Akinori Kyushu Univ. Fac. of Med. Professor, 医学部, 教授 (00132738)
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| Co-Investigator(Kenkyū-buntansha) |
MITSUIYE Tamotsu Kyushu Univ. Fac. of Med. Research Associate, 医学部, 助手 (40174065)
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| Project Period (FY) |
1988 – 1989
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| Keywords | single cardiac myocyte / Na / Ca exchange / ion exchange / intracellular Ca / patch clamp technique |
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| Research Abstract |
The intracellular Ca^<2+> concentration is lower by 10^4 than the extracellular Ca^<2+> concentration. This concentration gradient is essential to achieve various kinds of cell functions, such as the muscle contraction, and electrical activity of the cell. The Na/Ca exchange mechanism is mainly responsible for pumping out Ca^<2+> which enters the cardiac muscle during the systolic period. The aim of our project is to determine the stoichiometry of the Na/Ca exchange by recording the Na/Ca exchange current. We clarified that the intracellular ion concentrations may change, if we stimulate the Na/Ca exchange continuously. Therefore, we used a holding potential which is equal to the theoretical equilibrium potential for the 3Na:1Ca exchange. The reversal potential of the Na/Ca exchange current were successfully measured at various external Na^+ and Ca^<2+> concentrations. The reversal potential was in agreement with the theoretical values of the 3Na:1Ca exchange.
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