ABSTRACT
<p><b>OBJECTIVE</b>To identify the effect of ethanol and its metabolite acetaldehyde on acetylcholine-sensitive K(+) channel Kir3.1 protein expression, and explore the potential role of this channel and acetaldehyde in arrhythmia caused by acute alcoholic intoxication.</p><p><b>METHODS</b>Primary atrial cardiomyocytes were isolated from 150 newborn SD rats by typsin and type II collagenase, cultured and troponin I was determined by immunofluorescence. Cell survival in 200-800 mmol/L ethanol or 50-500 µmol/L acetaldehyde treated cells for 24 hours was measured by CCK-8 assay to determine the concentration of ethanol and acetaldehyde for inducing apoptosis in cardiomyocytes. The highest non-apoptotic concentration (200 mmol/L) of ethanol and acetaldehyde (100 µmol/L) was used in the main study. Kir3.1 protein expression was detected by Western blot.</p><p><b>RESULTS</b>(1) Cellular immunofluorescence results showed that cultured cells are cardiomyocytes, and more than 90% of these cells are troponin I positive. (2) CCK-8 assay demonstrated that the survival rate of cardiomyocytes in the groups treated by ethanol over 400 mmol/L for 24 hours or acetaldehyde over 400 µmol/L was significantly lower than that of the control group (P < 0.05), while the survival rate was similar in cardiomyocytes treated by ethanol less than 200 mmol/L or acetaldehyde less than 350 µmol/L for 24 hours and the control group (P > 0.05). (3) Western-bolt assay revealed that ethanol and acetaldehyde treatment for 24 hours upregulated Kir3.1 protein expression in primary atrial cardiomyocytes of newborn SD rats by (44.52 ± 23.07)% and (45.04 ± 22.01)% respectively compared with the control group (all P < 0.01).</p><p><b>CONCLUSIONS</b>Acute ethanol and acetaldehyde treatment could significantly upregulate the protein expression of acetylcholine-sensitive K(+) channel Kir3.1, this might serve as a potential mechanism for arrhythmia caused by acute alcoholic intoxication.</p>