Membrane actions of ethanol on rabbit sino-atrial node studied by voltage clamp method.
Electrophysiological effects of ethanol on rabbit sino-atrial node were studied by means of the double-microelectrode voltage clamp method. In spontaneously beating preparations, ethanol (above 1%) decreased the maximum rate of depolarization of the action potential. Furthermore, 3% ethanol produced a significant decrease in the action potential amplitude, the action potential duration at 50% repolarization and the rate of the diastolic depolarization. Of the current systems, voltage clamp studies showed that ethanol reduced the slow inward current, the time-dependent potassium outward current and the hyperpolarization activated inward current. These observations indicate that ethanol does not have an effect on a single current system, but directly modifies the spontaneous discharge of sino-atrial node pacemaker cells due to a reduction of the time-dependent current systems.
Kotake
H
H
1st Department of Internal Medicine, Tottori University School of Medicine, Yonago, Japan.
Hirai
S
S
Nawada
T
T
Kurata
Y
Y
Watanabe
M
M
Hisatome
I
I
Hasegawa
J
J
Mashiba
H
H
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004594:Electrophysiology; D000431:Ethanol / Q000494:pharmacology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D011817:Rabbits; D012849:Sinoatrial Node / Q000187:drug effects* / Q000502:physiology
D002121:Calcium Channel Blockers; D000431:Ethanol