Action of nicotine on the electroplax and difference of potency between ionized and unionized forms

Biochimica et Biophysica Acta (BBA) - Specialized Section on Biophysical Subjects Pub Date : 1964-05-25 DOI:10.1016/0926-6577(64)90216-5

Eva Bartels, Thomas R. Podleski

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引用次数: 13

Abstract

The effect of nicotine and the pH dependence of its potency were tested on the monocellular electroplax preparation of Electrophorus.

1. Nicotine (5·10⁻⁵M) blocks the action potential reversibly within 5 min. The stepwise depolarization of the membrane by increasing concentrations is shown.
2. Curare inhibits the effect of nicotine. Both compounds act at the synapse only. The mode of action is competitive. In contrast, the toxin obtained from clam affects the preparation without interference with the effect of nicotine.
3. Increasing the pH from 6.2 to 9.0 decreases the potency of nicotine by a factor of 2–3 and, in addition, increases the time required for reaching the equilibrium potential by a factor of 5–10.
4. The degree of ionization of nicotine has been evaluated in relation to potency of action.

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尼古丁对电激电位的作用及其电离型和非电离型电激电位的差异

研究了烟碱对单细胞电火花制备的影响及其对pH值的依赖性。尼古丁(5·10−5M)在5 min内可逆地阻断动作电位。随着浓度的增加，膜逐渐去极化。Curare能抑制尼古丁的作用。这两种化合物都只作用于突触。行动模式是竞争性的。相反，从蛤蜊中获得的毒素影响制备，而不干扰尼古丁的作用。将pH值从6.2增加到9.0，尼古丁的效价降低了2-3倍，另外，达到平衡电位所需的时间增加了5-10.4倍。尼古丁的电离程度已经根据作用的效力进行了评估。

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Biochimica et Biophysica Acta (BBA) - Specialized Section on Biophysical Subjects

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