INACTIVATION OF THE SODIUM CURRENT IN SQUID GIANT-AXONS BY HYDROCARBONS
INACTIVATION OF THE SODIUM CURRENT IN SQUID GIANT-AXONS BY HYDROCARBONS
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DOI：
10.1016/s0006-3495(85)83817-0
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发表时间：
1985-01-01
影响因子：
3.4
通讯作者：
NEEDHAM, D
中科院分区：
文献类型：
--
作者：
ELLIOTT, JR;HAYDON, DA;NEEDHAM, D
已知鱿鱼巨轴突中钠电流的稳态失活参数 (h.infin.) 的电压依赖性会因碳氢化合物而向超极化方向移动，并且有人提出这种变化是由轴突膜厚度变化引起的，类似于脂质双层中产生的变化（Haydon, D.A. 和 J.E. Kimura, 1981, J. Physiol. [Lond.], 312:57-70；Haydon, D.A. 和 B.W. Urban，1983，J. Physiol，338：435-450；Haydon，D.A.、J.R. Elliott 和 B.M. Hendry，1984 年，《Curr. Top》，22：445-482。通过检查一系列浓度的环戊烷对轴突膜和由油酸甘油酯加角鲨烯形成的脂质双层的每单位面积高频电容的影响，系统地测试了该假设。对环丙烷和正丁烷进行了类似的比较，压力均为 1 atm。结果与轴膜厚度增加导致 h.infin 偏移的观点一致。然而，除非浓度非常高，脂质双层的厚度变化太小，无法解释 h.infin。轮班。讨论了这一发现的可能解释。
The voltage dependence of the steady state inactivation parameter (h.infin.) of the sodium current in the squid giant axon is known to be shifted in the hyperpolarizing direction by hydrocarbons and it has been suggested that the shifts arise from thickness changes in the axon membrane, analagous to those produced in lipid bilayers (Haydon, D.A., and J.E. Kimura, 1981, J. Physiol. [Lond.], 312:57-70; Haydon, D.A., and B.W. Urban, 1983, J. Physiol. [Lond.], 338:435-450; Haydon, D.A., J.R. Elliott, and B.M. Hendry, 1984, Curr. Top, Membr. Transp., 22:445-482). This hypothesis has been tested systematically by examining the effects of a range of concentrations of cyclopentane on the high-frequency capacitance per unit area both of the axonal membrane and of lipid bilayers formed from monoolein plus squalene. A similar comparison has been made for cyclopropane and n-butane, both at a pressure of 1 atm. The results are consistent with the notion that thickness increases in the axolemma produce the shift in h.infin.. Except at very high concentrations, however, the thickness changes in the lipid bilayer were too small to account for the h.infin. shifts. A possible explanation of this finding is discussed.