Musso E, Vassalle M
Cardiology. 1977;62(4-6):322-31. doi: 10.1159/000169866.
The effect of theophylline on potassium uptake of cardiac Purkinje fibers was studied under different conditions. The following results were obtained: (1) theophylline decreases K uptake and enhances Purkinje fiber automaticity; (2) norepinephrine and high [Ca]0 counteract the decrease in K uptake induced by theophylline; (3) adrenergic receptor blockers do not modify the effect of theophylline on K uptake; (4) norepinephrine increases K uptake and this effect is potentiated by theophylline and is little affected by imidazole and acetylcholine. It is concluded that theophylline may depress K uptake by releasing intracellular calcium and thereby inhibiting the sodium-potassium pump. However, theophylline potentiates the effect of norepinephrine on K uptake probably by enhancing the intracellular levels of cyclic AMP.
在不同条件下研究了茶碱对心脏浦肯野纤维钾摄取的影响。得到以下结果：（1）茶碱降低钾摄取并增强浦肯野纤维的自律性；（2）去甲肾上腺素和高[Ca]0可抵消茶碱诱导的钾摄取减少；（3）肾上腺素能受体阻滞剂不改变茶碱对钾摄取的作用；（4）去甲肾上腺素增加钾摄取，茶碱可增强此作用，而咪唑和乙酰胆碱对此作用影响较小。得出结论：茶碱可能通过释放细胞内钙从而抑制钠钾泵来降低钾摄取。然而，茶碱可能通过提高细胞内环磷酸腺苷水平来增强去甲肾上腺素对钾摄取的作用。
