|
KMID : 0377519840090030269
|
|
Chung-Ang Journal of Medicine
1984 Volume.9 No. 3 p.269 ~ p.277
|
|
|
Effect of Vanadate on Action Potentials of Rabbit S-A node
|
|
Cho Yong-Moon
Bang Hyo-Weon
Uhm Dae-Yong
Rhee Sang-Don
|
|
|
Abstract
|
|
|
|
In order to investigate the electrphysiological effect of vanadate, a potent inhibitor of Na^+-K^+ pump, on the cardiac muscle, the alteration of transmembrane potential as influenced by the drug was measured in rabbit SA rodes in vitro by means of KCI glass intracellular microelectrodes. The followings were results of findings: 1. The rate of spontaneous firing was decreased in the presence of vanadate and the maximum inhibition which was about 50% of contral level was obtained at drug concentrations of 10^-3 M or higher. 2. The maximum diastolic potential(M.D.P.) was depressed by vanadate in a dose-dependent manner and the maximum inhibitory effect was obtained at the drug concentration of 10^-3 M. However the peripheral pacemaker cells were more resistant to the drug effect than the central pacemaker cells at lower concentrations of the drug. 3. In both central and perepheral pacemaker cells, vanadate had no effect on the M.D.P. in concentrations up to 5×10^-4 M. However on at 5×10^-2 M, the drug depressed the M.D.P. in the peripheral cells. 4. Changes of the action potential induced by vanadate were qualitatively similar to those occuring when the calcium concentration of the bathing medium was raised to 4mM. These results may be interpreted as that vanadate increases the rate of Ca^++ influx info the cell in S-A nodes.
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|