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KMID : 0382619890090010315
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Hanyang Journal of Medicine
1989 Volume.9 No. 1 p.315 ~ p.328
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Electrophysiological Effects of Vanadate on the Atrial Muscle, Atrioventricular Node Cells and Purkinje Fiber of the Rabbit Heart
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Abstract
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Vanadium, a trace element essential for normal growth of animals was recently found to be a potent inhibitor of Na-K ATPase. Although the cellular activity of vanadate is known to be similar to that of ouabain in some respect, it does not faithfully mimic all of the effect of the cardiac glycosides.
It has been known that vanadate influences cardiovascular functions in the anesthetized and conscious animals as well. In the present study, electrophysiological effects of vanadate on the rabbit cardiac cells were investigated.
The results obtained were as follows;
1. Following superfusion with vanadate (30-250 M) solution the maximum diastolic potential (MDP) of the rabbit atrial muscle cell decreased significantly while the overshoot potential (OS) was increased only after superfusion with 150 and 250 pM vanadate solution. And also vanadate (30-250 M) significantly increased the action potential amplitude from 7 minutes to 15-20 minutes after onset of super-fusion.
2. The vanadate in all the concentrations decreased the rate of spontaneous firing (RSF) of the atrial muscle cell whereas in 15-30 M concentration it significantly prolonged the action potential duration (APD6o)
3. The action potential amplitude and APD6o of atrioventricular node cells were not altered by vanadate, but RSF decreased remarkably after superfusion of these cells with 100-250 M vanadate solution.
4. The vanadate (250 M) decreased MDP and increased APA of the rabbit Purkinje cells.
5. Superfusion of the Purkinje fibers with vanadate solution resulted in a prominent decrease in RSF. On the other hand, APD6o of these fibers was significantly pro-longed after superfusion with 150-250 M vanadate solutions.
The results of present study indicate that electrophysiological effects of vanadate on the atrial muscle cell and Purkinje fibers are more prominent than that on the atrioventricular node cells and that effect of vanadate on RSF of the rabbit atrial cells is :-ost pronounced.
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KEYWORD
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