离体蟾蜍皮肤中钠泵驱动力（ENa）以及主动和被动电导（GNa和Gsh）的测定：抗利尿激素的影响 - Suppr | 超能文献

离体蟾蜍皮肤中钠泵驱动力（ENa）以及主动和被动电导（GNa和Gsh）的测定：抗利尿激素的影响

Determination of the driving force for the sodium pump (ENa) and of active and passive conductances (GNa and Gsh) in isolated toad skin: influence of antidiuretic hormone.

Concha J B, Norris B C, Contreras G M, Palacios S M, González C S

Department of Physiological Sciences, Faculty of Biological and Natural Sciences, University of Concepción, Chile.

Gen Pharmacol. 1987;18(6):589-92. doi: 10.1016/0306-3623(87)90028-0.

Abstract

Values of the sodium potential (ENa), active conductance (GNa) and passive conductance (Gsh) were measured in the isolated skin of the toad Pleurodema thaul placed in an Ussing chamber, and Isaacson's test was performed with 2,4,6-trieminopyrimidine (TAP) and with amiloride. 2. The numerical estimates obtained in the presence of TAP were ENa 122.85 +/- 15.17 mV, GNa 0.493 +/- 0.09 mS/cm2 and Gsh 1.145 +/- 0.23 mS/cm2. 3. After exposure to ADH these values were as follows: ENa 85.76 +/- 12.17 mV, GNa 1.191 +/- 0.20 mS/cm2 and Gsh 0.935 +/- 0.14 mS/cm2. 4. Addition of 0.5 x 10(2-) TAP produced a 53.90 +/- 5.10% decrease in transepithelial potential and a 37.90 +/- 4.90% fall in short-circuit current. 5. Exposure to ADH increased the transepithelial potential difference 34.20 +/- 13.20% and the short-circuit current to 78.00 +/- 20.50% above the control values. 6. Comparison of the efficiency and mechanism of action of TAP and amiloride in the determination of electrical parameters shows that both agents induce a similar decrease in Gsh, a finding which could indicate that TAP blocks toad skin apical membrane Na+ channels without affecting tight junction conductance.

摘要

在置于尤斯灌流小室的蟾蜍（Pleurodema thaul）离体皮肤中测量钠电位（ENa）、主动电导（GNa）和被动电导（Gsh）的值，并用2,4,6-三氨基嘧啶（TAP）和氨氯吡咪进行艾萨克森试验。2. 在TAP存在下获得的数值估计为：ENa 122.85±15.17 mV，GNa 0.493±0.09 mS/cm²，Gsh 1.145±0.23 mS/cm²。3. 暴露于抗利尿激素（ADH）后，这些值如下：ENa 85.76±12.17 mV，GNa 1.191±0.20 mS/cm²，Gsh 0.935±0.14 mS/cm²。4. 添加0.5×10⁻²的TAP使跨上皮电位降低53.90±5.10%，短路电流降低37.90±4.90%。5. 暴露于ADH使跨上皮电位差比对照值增加34.20±13.20%，短路电流增加78.00±20.50%。6. 比较TAP和氨氯吡咪在确定电参数方面的作用效率和机制表明，两种药物均导致Gsh出现类似程度的降低，这一发现可能表明TAP阻断蟾蜍皮肤顶端膜Na⁺通道而不影响紧密连接电导。