Kirk M D, Scheller R H
Proc Natl Acad Sci U S A. 1986 May;83(9):3017-21. doi: 10.1073/pnas.83.9.3017.
This report presents studies on ionic currents in Aplysia motoneuron B16 that are modulated by the neuropeptide egg-laying hormone (ELH) of Aplysia. ELH induces an inward current that persists in the presence of the peptide and that decays slowly after ELH is removed from the bath. The effect is not due to a decrease in the delayed potassium current, the calcium-activated potassium current, or the transient potassium current. Current-voltage measurements indicate that ELH produces increased inward currents from -80 mV to approximately equal to 0 mV. The effect is particularly enhanced in the region from -40 mV to -25 mV where a negative slope conductance due to voltage-dependent slow inward current is observed. The slow inward current and the response to ELH persist in saline solutions in which Ca2+ is replaced with Co2+ but are eliminated when Na+ is replaced with equimolar concentrations of either Tris or N-methyl-D-glucamine. The response to ELH is unaffected by replacing chloride with equimolar acetate; by increasing the potassium concentration; or by adding tetraethylammonium chloride, CsCl, 4-amino-pyridine, or tetrodotoxin to the saline bath. In addition, the reversal potentials for the ELH response (range, -28 to +46 mV), obtained from difference current-voltage relationships, are consistent with an increase in the Na+-dependent slow inward current. We conclude that at least one of the effects of ELH on B16 is to increase a slow inward current carried by Na+.
本报告展示了对海兔运动神经元B16中离子电流的研究，这些电流受海兔神经肽产卵激素（ELH）的调节。ELH诱导出一种内向电流，该电流在肽存在时持续存在，并且在从浴槽中去除ELH后缓慢衰减。这种效应并非由于延迟钾电流、钙激活钾电流或瞬时钾电流的减少。电流-电压测量表明，ELH在-80 mV至约等于0 mV的范围内产生增加的内向电流。在-40 mV至-25 mV的区域中，这种效应尤其增强，在该区域观察到由于电压依赖性缓慢内向电流导致的负斜率电导。当Ca2+被Co2+取代时，缓慢内向电流和对ELH的反应在盐溶液中持续存在，但当Na+被等摩尔浓度的Tris或N-甲基-D-葡糖胺取代时则消失。用等摩尔乙酸盐取代氯离子、增加钾浓度或向盐浴中添加氯化四乙铵、CsCl、4-氨基吡啶或河豚毒素，对ELH的反应均无影响。此外，从差分电流-电压关系获得的ELH反应的反转电位（范围为-28至+46 mV）与Na+依赖性缓慢内向电流的增加一致。我们得出结论，ELH对B16的影响至少有一个是增加由Na+携带的缓慢内向电流。
