乌头碱和藜芦生物碱对青蛙骨骼肌的不同作用。

Different actions of aconitine and veratrum alkaloids on frog skeletal muscle.

Nánási P P, Kiss T, Dankó M, Lathrop D A

Department of Physiology, University Medical School of Debrecen, Hungary.

Gen Pharmacol. 1990;21(6):863-8. doi: 10.1016/0306-3623(90)90446-s.

Abstract

The electrophysiological effects of veratridine, cevadine and aconitine (10(-8)-2 x 10(-4), 2 x 10(-7)-2 x 10(-6) and 2 x 10(-6)-10(-4) mol/l, respectively) were compared on frog muscle membrane using conventional microelectrodes. 2. Veratridine and aconitine were equally effective in depolarizing the resting membrane with the threshold concentration of 5 x 10(-5) mol/l. 3. Volleys of repetitive discharges and slow transient depolarizations were observed when single electrical stimuli were applied in the presence of veratridine (5 x 10(-8)-2 x 10(-5) mol/l), but not aconitine. Volleys with aconitine could be evoked only by repetitive stimulation; however no tendency of repolarization was observed following these volleys. Two orders of magnitude more aconitine than veratridine was required to induce volleys with similar parameters. 4. The effects of cevadine were similar to those of the corresponding concentrations of veratridine. 5. The observed differences between the electrophysiological actions of aconitine and veratrum alkaloids may be explained in part with differences in Na+ channel inactivation produced by these toxins, in addition to differences in their use-dependent behavior.

摘要

使用传统微电极，比较了藜芦定、瑟瓦定和乌头碱（分别为10⁻⁸ - 2×10⁻⁴、2×10⁻⁷ - 2×10⁻⁶和2×10⁻⁶ - 10⁻⁴mol/L）对蛙肌膜的电生理效应。2. 藜芦定和乌头碱在使静息膜去极化方面效果相同，阈值浓度为5×10⁻⁵mol/L。3. 当在藜芦定（5×10⁻⁸ - 2×10⁻⁵mol/L）存在的情况下施加单个电刺激时，观察到重复放电群和缓慢的瞬时去极化，但乌头碱不存在这种情况。乌头碱引发的放电群只能通过重复刺激诱发；然而，在这些放电群之后未观察到复极化趋势。诱导具有相似参数的放电群所需的乌头碱浓度比藜芦定高两个数量级。4. 瑟瓦定的作用与相应浓度的藜芦定相似。5. 观察到的乌头碱和藜芦生物碱电生理作用之间的差异，除了它们使用依赖性行为的差异外，部分可能由这些毒素产生的Na⁺通道失活差异来解释。