Ito H, Takikawa R, Iguchi M, Hamada E, Sugimoto T, Kurachi Y
2nd Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Pflugers Arch. 1990 Sep;417(1):126-8. doi: 10.1007/BF00370783.
The effects of heparin on activation of the G protein-gated muscarinic K+ channel were examined in atrial cells of guinea-pig heart. The inside-out patch clamp technique was used. The pipette solution contained 1.1 microM acetylcholine (ACh). In the inside-out patches, intracellular GTP activated the muscarinic, K+ channel. When heparin (0.05-5 units/ml) was further added to the intracellular side of the patch membrane, the channel openings were depressed in a concentration-dependent fashion. The effects of heparin were reversible after wash-out. Heparin did not affect GTP-gamma S-induced activation of the K+ channel. Therefore, it is suggested that heparin may uncouple the muscarinic receptors from GK protein in the cardiac atrial cell membrane.
在豚鼠心脏心房细胞中研究了肝素对G蛋白门控毒蕈碱型钾通道激活的影响。采用内面向外膜片钳技术。移液管溶液含有1.1微摩尔乙酰胆碱（ACh）。在内面向外膜片中，细胞内GTP激活毒蕈碱型钾通道。当将肝素（0.05 - 5单位/毫升）进一步添加到膜片膜的细胞内侧时，通道开放以浓度依赖方式受到抑制。洗脱后肝素的作用是可逆的。肝素不影响GTP-γS诱导的钾通道激活。因此，提示肝素可能使心房细胞膜中毒蕈碱受体与GK蛋白解偶联。
