哇巴因对离体蛙胃黏膜的作用。

Effects of ouabain on frog gastric mucosa in vitro.

作者信息

Carrasquer G, Chu T C, Schwartz M, Holloman T L, Rehm W S

出版信息

Biochim Biophys Acta. 1981 Jan 22;640(2):512-20. doi: 10.1016/0005-2736(81)90475-2.

Abstract

The effect of the addition of ouabain to the nutrient solution was determined on resistance, potential difference (p.d.) and H+ secretion rate. In NaCl media, 10(-3) M ouabain decreased significantly the p.d. from 25.6 mV to 16.1 mV in 30 min and to 11.0 mV in 60 min. No significant changes occurred in resistance and H+ secretion rate. In Na2SO4 (Cl(-)-free) media, ouabain produced a biphasic effect on p.d. The p.d. changed from -28.0 mV (nutrient-negative) to a nadir of -37.4 mV in 7 min and then increased to -16.4 mV in 60 min. At the nadir there was no significant change in resistance or H+ secretion rate but at 60 min, unlike Cl- media, resistance increased by 36% and H+ secretion rate decreased by 43%. To decide whether the ouabain-caused decrease in H+ rate in Na2SO4 media was due to an effect on the H+ pump or on resistance of the return pathways, the voltage was clamped at 0 and 40 mV. Clamping the voltage showed that in the case of a marked decrease in the H+ secretion rate, the H+ transport mechanism itself was inhibited (and not the parallel pathway). The decrease in p.d. due to ouabain in Cl- and SO42- media indicates that the (Na+ + K+)-ATPase mechanism may be electrogenic.

摘要

测定了向营养液中添加哇巴因对电阻、电位差（p.d.）和H⁺分泌速率的影响。在NaCl培养基中，10⁻³M哇巴因在30分钟内使电位差从25.6mV显著降至16.1mV，60分钟内降至11.0mV。电阻和H⁺分泌速率无显著变化。在Na₂SO₄（无Cl⁻）培养基中，哇巴因对电位差产生双相作用。电位差在7分钟内从-28.0mV（营养液为负）降至最低点-37.4mV，然后在60分钟内升至-16.4mV。在最低点时，电阻和H⁺分泌速率无显著变化，但在60分钟时，与Cl⁻培养基不同，电阻增加了36%，H⁺分泌速率下降了43%。为了确定哇巴因导致Na₂SO₄培养基中H⁺速率降低是由于对H⁺泵的影响还是对返回途径电阻的影响，将电压钳制在0和40mV。电压钳制表明，在H⁺分泌速率显著降低的情况下，H⁺转运机制本身受到抑制（而非平行途径）。Cl⁻和SO₄²⁻培养基中哇巴因导致的电位差降低表明（Na⁺+K⁺）-ATP酶机制可能是生电的。