| Objectives The effects of acute alcohol intervention on atrial myocyticion channels and action potential in guinea pig were observed to investigate how alcohol changes the atrial myocytes' electrophysiological character and induces arrhythmia.Methods Guinea pig atrial myocytes were obtained by enzymolysis. Whole-cell patch clamp, was used to gain the I-V curve, availability curve and activity curve of L-type calcium channel current (ICa.L) and voltage-dependent sodium channel current (I(Na(), as well as I-V curve of delayed rectifier potassium channel , with or without ethanol in various concentrations. Guinea pig's heart keeping beating with continuous perfusion by a Langendorff system, the effects of alcohol in various concentrations on the sinus cardiac cycle(SCL), effective refractory period(ERP) and monophasic action potential(MAP) of the atrium were recorded by a multi-channel electrophysiolograph.Results 1. The I-V curves of ICa.L were changed by alcohol in aconcentration-dependent way. Inhibition occurred when the alcohol concentration was less than 45mmol/L, while enhancement with a concentration more than 50mmol/L. A sudden alternation between the two effects was observed with the alternation between the two concentrations. A higher concentration to 80mmol/L did not change the I-V curve. Alcohol did not change the activity curve or availability curve of ICa.L except the former in an 80mmol/L concentration.2. Acute alcohol intervention did not change the I-V curve, activity curve, availability curve or resting availability curve of lNa.3. 40mmol/L, but not 24mmol/L or 80mmol/L alcohol could inhibit Ik, and this effect mainly owe to the inhibition to the rapidly activating component of Ik (Iitr). 40mmol/L and 80mmol/L alcohol could inhibit Ikf but the slowly activating component (1 |
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