McCall D, Ryan K
J Mol Cell Cardiol. 1987 May;19(5):453-63. doi: 10.1016/s0022-2828(87)80397-8.
To further define the sarcolemmal effects of ethanol and acetaldehyde, their effects on Na pump function were studied in synchronously contracting monolayers of neonatal rat myocardial cells. The effects of ethanol (10 mg/dl to 1000 mg/dl: 2 X 10(-3) M-0.2 M) and acetaldehyde (10(-6) M to 10(-4) M) on total 42K influx, ouabain-sensitive 42K influx, Na pump density (from specific 3H-ouabain binding) and pump turnover rates were measured. Applied acutely ethanol had no effect on 42K influx but after 30 min of treatment 42K influx was decreased by 13%, 23% and 48% in 100 mg/dl, 300 mg/dl and 1000 mg/dl ethanol respectively. This primarily reflected a decrease in mean ouabain-sensitive K+ influx from a control of 12.54 to 9.90, 8.95 and 6.68 (p-mol/cm2/s) in 100, 300 and 1000 mg/dl (2 X 10(-2) M, 6 X 10(-2) M) ethanol. Acetaldehyde in the concentrations tested had no effect on K+ influx. Ethanol treatment produced a decrease in Na pump density, maximum within 30 min and dose-dependent, at concentrations of 100 mg/dl (22%), 300 mg/dl (37%) and 1000 mg/dl (55%). Acetaldehyde had no effect on Na pump density. In the presence of ethanol (300 mg/dl and 1000 mg/dl) intracellular Na+ increased significantly and the Na+ efflux declined in parallel with the K+ influx. From the ouabain-sensitive K+ and Na+ fluxes and the Na pump density individual pump turnover rates were calculated at 62.5/s in control cells and 66/s and 84/s in cells treated with 300 mg/dl (6 X 10(-2) M) and 1000 mg/dl (0.2 M) respectively. We conclude that ethanol, but not acetaldehyde has a depressant effect on sarcolemmal Na pump function. The results suggest this is due primarily to a decrease in the number of sarcolemmal Na pump sites.
为了进一步明确乙醇和乙醛对肌膜的影响，我们在新生大鼠心肌细胞同步收缩的单层培养物中研究了它们对钠泵功能的作用。测定了乙醇（10mg/dl至1000mg/dl：2×10⁻³M - 0.2M）和乙醛（10⁻⁶M至10⁻⁴M）对总⁴²K内流、哇巴因敏感的⁴²K内流、钠泵密度（通过特异性³H - 哇巴因结合测定）和泵周转率的影响。急性应用乙醇对⁴²K内流无影响，但处理30分钟后，100mg/dl、300mg/dl和1000mg/dl乙醇分别使⁴²K内流降低了13%、23%和48%。这主要反映了平均哇巴因敏感的K⁺内流从对照的12.54降至100、300和1000mg/dl（2×10⁻²M、6×10⁻²M）乙醇处理后的9.90、8.95和6.68（p - mol/cm²/s）。所测试浓度的乙醛对K⁺内流无影响。乙醇处理使钠泵密度降低，在30分钟内达到最大值且呈剂量依赖性，在100mg/dl（22%）、300mg/dl（37%）和1000mg/dl（55%）浓度下。乙醛对钠泵密度无影响。在存在乙醇（300mg/dl和1000mg/dl）时，细胞内Na⁺显著增加，且Na⁺外流与K⁺内流平行下降。根据哇巴因敏感的K⁺和Na⁺通量以及钠泵密度计算出单个泵的周转率，对照细胞为62.5/s，用300mg/dl（6×10⁻²M）和1000mg/dl（0.2M）处理的细胞分别为66/s和84/s。我们得出结论，乙醇而非乙醛对肌膜钠泵功能有抑制作用。结果表明这主要是由于肌膜钠泵位点数量减少所致。
