Membrane Currents in the Atrioventricular Node of the Rabbit
방실결절의 세포막 이온전류에 관한 연구

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Ho, Won Kyung; Kim, Woo Gyeum; Earm, Yung E
Issue Date
Seoul National University College of Medicine
Seoul J Med 1986;27(3):211-231
Two microelectrode voltage clamp techniqueSlow inward currentHyperpolarization activated inward currentPump currentAV node
The rabbit AV node was isolated and dissected into small strips of 0.3 mm
width to apply two microelectrode voltage clamp technique. Then, slow inward current (isJ,
hyperpolarization activated inward current (if) and pump current were recorded and their
kinetic properties were analysed.
The results obtained were as follows:
1. The isolated AV node continued to beat, but the rate was slower than that in the SA
node. The configuration of action potential showed regional difference. Small AV node
preparations also showed spontaneous action potentials whose configurations were similar to
those in the SA node. Resting membrane potential was about -40 mV.
2. On depolarization from the holding potential of -40 mV to various potential level, slow
inward current (isf) was recorded. It was disappeared by adding 2 mM Mn+ + and increased
remarkably by 10-6M adrenaline. Current-voltage relationship, steady-state inactivation and
recovery from inactivation were also studied and considered similar to those in other cardiac
3. In response to hyperpolarizing voltage clamp pulse, the current if was activated. The
reversal potential was about -25 mV. 0.5 mM Cs" decreased if in a voltage-dependent
manner. 10-6M adrenaline showed little effect on if.
4. The activity of electrogenic Na+ pump was demonstrated by K+ -induced transient
outward current or transient hyperpolarization after pre-treatment with K+-free Tyrode solution.
The pump activity was affected by duration of pre-treatment, K+ concentration in
recovery solution and Ca + + concentration in K+ -free Tyrode solution.
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College of Medicine/School of Medicine (의과대학/대학원)Dept. of Medicine (의학과)The Seoul Journal of MedicineThe Seoul Journal of Medicine Vol. 27 No.3 (1986)
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