Miljkovic Z, MacDonald J F
Brain Res. 1986 Jun 25;376(2):396-9. doi: 10.1016/0006-8993(86)90207-6.
The blocking of excitatory amino acid currents by pentobarbital was studied in cultured hippocampal neurons. Peak amino acid currents were plotted against holding potential prior to and following bath applications of pentobarbital. The divalent cation Mg2+ was not added either to the recording or extracellular solution. As a consequence, current-voltage curves were approximately linear regardless of the excitatory amino acid employed. Kainic acid (KAI) currents were more sensitive to blockade by pentobarbital than were those activated by L-aspartic acid (L-Asp). However, blockade of all currents (including those for KAI) was more pronounced at hyperpolarized values than at comparable depolarized potentials (i.e. in the presence of the same driving force). Furthermore, the voltage-dependence of the pentobarbital blockade was greater for L-Asp than for KAI. Since pentobarbital is neutrally charged (or weakly negative) under the present recording conditions, the voltage-sensitivity of its block must arise from the influence of membrane field upon the site of the block rather than upon the access of the blocking molecule to this site.
在培养的海马神经元中研究了戊巴比妥对兴奋性氨基酸电流的阻断作用。在浴加戊巴比妥之前和之后，将峰值氨基酸电流相对于钳制电位作图。记录溶液和细胞外溶液中均未添加二价阳离子Mg2+。因此，无论使用何种兴奋性氨基酸，电流-电压曲线大致呈线性。与L-天冬氨酸（L-Asp）激活的电流相比，海人酸（KAI）电流对戊巴比妥的阻断更敏感。然而，在超极化值时，所有电流（包括KAI电流）的阻断比在相当的去极化电位时（即在相同驱动力存在下）更明显。此外，戊巴比妥对L-Asp电流阻断的电压依赖性大于对KAI电流的阻断。由于在当前记录条件下戊巴比妥呈中性电荷（或弱负电荷），其阻断的电压敏感性必定源于膜电场对阻断位点的影响，而非源于阻断分子对该位点的接近。
