Rock D M, Macdonald R L
Neuroscience Program, University of Michigan, Ann Arbor 48104-1687.
Mol Pharmacol. 1992 Jan;41(1):83-8.
Spermine potentiates the action of N-methyl-D-aspartate (NMDA) at micromolar concentrations but is less effective at millimolar concentrations. In cultured cortical neurons we demonstrate that spermine enhances NMDA receptor currents in a unique manner. At low concentrations (1-10 microM) spermine enhances NMDA receptor current by increasing channel opening frequency, and at higher concentrations (greater than 10 microM) it produces, in addition, a voltage-dependent decrease in channel amplitude and average open time that limits its enhancing action. It is likely that these two actions of spermine, due to differences in concentration and voltage dependence, are mediated by independent sites on the NMDA receptor complex.
精胺在微摩尔浓度下可增强N-甲基-D-天冬氨酸（NMDA）的作用，但在毫摩尔浓度下效果较差。在培养的皮层神经元中，我们证明精胺以独特的方式增强NMDA受体电流。在低浓度（1-10微摩尔）时，精胺通过增加通道开放频率来增强NMDA受体电流，而在较高浓度（大于10微摩尔）时，它还会导致通道幅度和平均开放时间的电压依赖性降低，从而限制其增强作用。由于浓度和电压依赖性的差异，精胺的这两种作用可能是由NMDA受体复合物上的独立位点介导的。
