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KMID : 0378619860030010067
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Baptist Hospital Medical Journal
1986 Volume.3 No. 1 p.67 ~ p.76
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Effects of Vanadate on the Calcium Flux of Cardiac muscle
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Abstract
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Effects of Vanadate on the Calcium Flux of Cardiac muscle Young Shiok park Department of Medical Science The Graduate School Yonsei University (Directed by Professor Doo Hee Kang, M.D., Ph.D.) Since it was proposed that vanadate may be an "ideal endogenous regulator of the Na**+, K**+ -ATPase activity (Cantley et aL, 1979), vanadate has been a subject of intensive research and a variety of its physiological effects have been described (Nechay, L984). In isolated guinea pig heart muscle vanadate shows a positive inotropic effect on ventricular muscled while it induces a negative inotropic effect on atriaL muscle. But its underlying mechanism has not been elucidated so far. Therefore, in this study the flux raters of calcium ion into and from guinea pig heart muscle were measured to throw some light on the underlying mechantsm, because those rates have been known to be closely related to the cardiac contractility and the results are suimnerized as follows: 1) Calcium efflux rates from the intracellular Ca**++ pool(compactment 4) of both guinea pig left atrium and right ventricle were significantly reduced by vanadate and their pool sizes were significantly increased by vanadate. 2) The nagnitude of calcium influx into left atrium was reduced by vanadate, whole the magnitude of calcium influx into right ventricle was not affected by vanadate. From these results, it may be concluded that the positive inotropic effect of vanadate on the ventricular muscle was due to a reduced efflux rate of calcilm ion and its negative inotropic effect on atrial muscle was the result of a reduced influx of calcium ion.
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