Campbell D T
J Gen Physiol. 1982 Nov;80(5):713-31. doi: 10.1085/jgp.80.5.713.
The effect of the plant alkaloid aconitine on sodium channel kinetics, ionic selectivity, and blockage by protons and tetrodotoxin (TTX) has been studied in frog skeletal muscle. Treatment with 0.25 or 0.3 mM aconitine alters sodium channels so that the threshold of activation is shifted 40-50 mV in the hyperpolarized direction. In contrast to previous results in frog nerve, inactivation is complete for depolarizations beyond about -60 mV. After aconitine treatment, the steady state level of inactivation is shifted approximately 20 mV in the hyperpolarizing direction. Concomitant with changes in channel kinetics, the relative permeability of the sodium channel to NH4,K, and Cs is increased. This altered selectivity is not accompanied by altered block by protons or TTX. The results suggest that sites other than those involved in channel block by protons and TTX are important in determining sodium channel selectivity.
在青蛙骨骼肌中研究了植物生物碱乌头碱对钠通道动力学、离子选择性以及质子和河豚毒素（TTX）阻断作用的影响。用0.25或0.3 mM乌头碱处理会改变钠通道，使激活阈值向超极化方向移动40 - 50 mV。与青蛙神经的先前结果相反，对于超过约-60 mV的去极化，失活是完全的。乌头碱处理后，失活的稳态水平向超极化方向移动约20 mV。伴随着通道动力学的变化，钠通道对NH4、K和Cs的相对通透性增加。这种改变的选择性并不伴随着质子或TTX阻断作用的改变。结果表明，除了质子和TTX阻断通道所涉及的位点外，其他位点在决定钠通道选择性方面也很重要。
