鬼笔环肽对蛙肌纤维电活动和机械活动的影响。

Effects of phalloidin on electrical and mechanical activity of frog muscle fibres.

作者信息

Cognard C, Nyambi G E, Potreau D, Raymond G

出版信息

Eur J Pharmacol. 1985 Mar 26;110(1):89-94. doi: 10.1016/0014-2999(85)90032-9.

Abstract

The effects of phalloidin (10(-15) to 10(-5) M) on isolated muscle fibres of the frog were investigated under current or voltage clamp conditions in a double mannitol gap device coupled to a mechanoelectric transducer which allowed the estimation of isometric tension. The toxin significantly increased the action potential duration and the amplitude of the associated contraction. Under voltage-clamp conditions, for a concentration range of 10(-14) to 10(-8) M, phalloidin reversibly decreased (up to 42.7% +/- 3.1) the fast outward potassium current responsible for the delayed rectification. For concentrations from 10(-8) to 10(-5) M, the toxin irreversibly reduced (up to 43.3% +/- 2.9) the amplitude of the contractile response. It is concluded that, in skeletal muscle fibre of frog, phalloidin acts at two different levels, one which may be located at the outer face of the surface membrane while the other may be located deeper within the cell.

摘要

在双甘露醇间隙装置中，利用与机电换能器相连的电流钳或电压钳条件，研究了鬼笔环肽（10⁻¹⁵至10⁻⁵M）对青蛙离体肌纤维的影响，该装置可用于估计等长张力。毒素显著增加动作电位持续时间和相关收缩的幅度。在电压钳条件下，对于10⁻¹⁴至10⁻⁸M的浓度范围，鬼笔环肽可逆地降低（高达42.7%±3.1）负责延迟整流的快速外向钾电流。对于10⁻⁸至10⁻⁵M的浓度，毒素不可逆地降低（高达43.3%±2.9）收缩反应的幅度。结论是，在青蛙骨骼肌纤维中，鬼笔环肽在两个不同水平起作用，一个可能位于表面膜的外表面，而另一个可能位于细胞内更深的位置。