Rafuse P E, Smith P A, Walker R J
Department of Pharmacology, University of Alberta, Edmonton, Canada.
Neuropharmacology. 1988 Jan;27(1):79-83. doi: 10.1016/0028-3908(88)90204-3.
The adrenaline-induced hyperpolarization of neurones in sympathetic ganglia of Rana pipiens was recorded by means of the sucrose gap technique. This hyperpolarization was inhibited in a concentration-dependent manner by sodium orthovanadate (0.1-1.0 mM). Although orthovanadate inhibited the hydrolysis of ATP by preparations of microsomal Na+/K+ ATPase from frog nerve (IC50 = 3.0 microM), extracellularly-applied orthovanadate did not inhibit electrogenic sodium pumping in intact sympathetic ganglia of Rana pipiens. This and other observations that extracellularly-applied orthovanadate did not enter sympathetic neurones and did not have access to intracellular enzyme systems. It is suggested that orthovanadate acts at an extracellular site to inhibit the adrenaline-induced hyperpolarization.
采用蔗糖间隙技术记录了肾上腺素引起的牛蛙交感神经节神经元超极化。原钒酸钠（0.1 - 1.0 mM）以浓度依赖的方式抑制这种超极化。虽然原钒酸钠抑制青蛙神经微粒体Na⁺/K⁺ATP酶制剂对ATP的水解（IC50 = 3.0 microM），但细胞外施加的原钒酸钠并不抑制牛蛙完整交感神经节中的生电钠泵。这以及其他观察结果表明，细胞外施加的原钒酸钠不会进入交感神经元，也无法作用于细胞内酶系统。提示原钒酸钠作用于细胞外位点以抑制肾上腺素诱导的超极化。
