Bressler B H, Phillis J W, Kozachuk W
Eur J Pharmacol. 1975 Aug;33(1):201-4. doi: 10.1016/0014-2999(75)90158-2.
Resting membrane potentials were recorded from the frog sartorius before and during exposure to noradrenaline (NA; 10(-2) M) in the presence or absence of ouabain (10(-3) M) and during manipulation of the extracellular potassium concentration. In potassium-free Ringer, NA produced no significant change in the resting membrane potential. With the extracellular potassium concentration at 2.5 or 5mM, NA caused a hyperpolarization. This reversed to a depolarization when extracellular K+ was greater than 7 mM. In all cases NA-induced changes were blocked by ouabain. These effects suggest that NA stimulates a membrane cation pump, the Na : K coupling ratio of which is affected by the available ion concentrations.
在存在或不存在哇巴因（10⁻³ M）的情况下，以及在细胞外钾浓度改变期间，记录青蛙缝匠肌在暴露于去甲肾上腺素（NA；10⁻² M）之前和期间的静息膜电位。在无钾的林格氏液中，NA对静息膜电位没有显著影响。当细胞外钾浓度为2.5或5 mM时，NA引起超极化。当细胞外K⁺大于7 mM时，这种情况逆转成去极化。在所有情况下，NA诱导的变化都被哇巴因阻断。这些效应表明，NA刺激了一种膜阳离子泵，其Na:K耦合比率受可用离子浓度的影响。
