Article date: December 1988
By: Hiroshi Kotake, Takahiro Nawada, Tatsuhiko Matsumoto, Hideyuki Kitamura, Takafumi Kaneda, Junichi Hasegawa, Hiroto Mashiba in Volume 95, Issue 4, pages 1175-1180
The effects of nizofenone fumarate were studied on the membrane potentials and currents of rabbit sino‐atrial node preparations by means of the double‐microelectrode voltage clamp method.
In spontaneously firing pacemaker cells, nizofenone (above 1 μm) decreased the heart rate. Above 3 μm, nizofenone reduced the maximum upstroke velocity, the amplitude of the action potential and the slope of the phase 4 depolarization, and prolonged the action potential duration at 50% repolarization.
Under voltage clamp conditions, nizofenone decreased the slow inward current and the time‐dependent potassium outward current in a dose‐dependent manner.
These findings suggest that nizofenone exerts an inhibitory action on the automaticity of sinoatrial node preparations via effects on both inward and outward currents.
The effects of nizofenone fumarate were studied on the membrane potentials and currents of rabbit sino‐atrial node preparations by means of the double‐microelectrode voltage clamp method.
In spontaneously firing pacemaker cells, nizofenone (above 1 μm) decreased the heart rate. Above 3 μm, nizofenone reduced the maximum upstroke velocity, the amplitude of the action potential and the slope of the phase 4 depolarization, and prolonged the action potential duration at 50% repolarization.
Under voltage clamp conditions, nizofenone decreased the slow inward current and the time‐dependent potassium outward current in a dose‐dependent manner.
These findings suggest that nizofenone exerts an inhibitory action on the automaticity of sinoatrial node preparations via effects on both inward and outward currents.
DOI: 10.1111/j.1476-5381.1988.tb11753.x
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