幼蛙（发育阶段小于或等于 XIX 期）皮肤中选择性差的阳离子通道。

Poorly selective cation channels in the skin of the larval frog (stage less than or equal to XIX).

作者信息

Hillyard S D, Zeiske W, Van Driessche W

出版信息

Pflugers Arch. 1982 Oct 1;394(4):287-93. doi: 10.1007/BF00583692.

Abstract

The abdominal skin of bullfrog larvae (Rana catesbeiana) was placed in an Ussing-type chamber, and its transepithelial electrical parameters were recorded with mucosal solutions of different ionic composition. With "K+-like" cations (K+, NH+4, RB+, Cs+) the power spectra of the fluctuations in short-circuit current displayed a Lorentzian component (fc = 30 - 40 Hz). The relaxation noise could be suppressed by addition of the K+ -channel blockers Ba2+ and TEA to the mucosal solution. Also, in presence of the ionophore antibiotic nystatin the Lorentizian noise was abolished. The Na+ -channel probes amiloride and benzimidazolyl-2-guanidine (BIG) both enhanced the relaxation noise obtained with the K+-like cations but, with Na+ and Li+, also caused the rise of a relaxation component above the background noise. In presence of amiloride or BIG, the addition of Ba2+, TEA and nystatin still abolished the Lorentizian noise. It can be concluded that the relaxation-noise source is located in the apical cell membranes of the tadpole skin. These spontaneously fluctuating cation channels do not seem to strictly discriminate between K+-like ions (K+, NH+4, Rb+, Cs+) and Na+-like ions (Na+, Li+). On the other hand, well-known specific probes for K+ channels (Ba2+, TEA) and for Na+ channels (amiloride, BIG) interact with this apical cation channel. It is possible that the poorly selective channel plays a role in the ontogenesis of the specific Na+ transport in the maturing frog skin.

摘要

将牛蛙幼体（牛蛙）的腹部皮肤置于尤斯灌流室中，并用不同离子组成的黏膜溶液记录其跨上皮电参数。使用“类钾”阳离子（K⁺、NH₄⁺、Rb⁺、Cs⁺）时，短路电流波动的功率谱显示出洛伦兹分量（fc = 30 - 40 Hz）。向黏膜溶液中添加钾通道阻滞剂Ba²⁺和TEA可抑制弛豫噪声。此外，在存在离子载体抗生素制霉菌素的情况下，洛伦兹噪声消失。钠通道探针氨氯吡脒和苯并咪唑基-2-胍（BIG）均增强了用类钾阳离子获得的弛豫噪声，但对于Na⁺和Li⁺，也导致了高于背景噪声的弛豫分量的上升。在存在氨氯吡脒或BIG的情况下，添加Ba²⁺、TEA和制霉菌素仍可消除洛伦兹噪声。可以得出结论，弛豫噪声源位于蝌蚪皮肤的顶端细胞膜中。这些自发波动的阳离子通道似乎并未严格区分类钾离子（K⁺、NH₄⁺、Rb⁺、Cs⁺）和类钠离子（Na⁺、Li⁺）。另一方面，众所周知的钾通道（Ba²⁺、TEA）和钠通道（氨氯吡脒、BIG）特异性探针与这种顶端阳离子通道相互作用。这种选择性较差的通道可能在成熟青蛙皮肤中特异性钠转运的个体发生中起作用。