Summary
Patch-clamp techniques were used to record pharmacologically-isolated N-methyl-D-aspartate-mediated excitatory postsynaptic currents (NMDA-EPSCs) from dentate granule cells in thin rat hippocampal slices. Membrane voltage modulated these EPSCs in two ways. Firstly, depolarization from resting potential enhanced EPSC amplitudes, as expected for a voltage-dependent block by Mg2+ of synaptically activated NMDA receptor channels. Secondly, depolarization markedly prolonged the time course of decay of NMDA-EPSCs in normal and low extracellular Mg2+. Both mechanisms were complementary in establishing a strong dependence between membrane potential and the amount of charge, namely Ca2+, transferred through synaptically activated NMDA receptor channels, that presumably underlies induction of long-term potentiation in the hippocampus.
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Konnerth, A., Keller, B.U., Ballanyi, K. et al. Voltage sensitivity of NMDA-receptor mediated postsynaptic currents. Exp Brain Res 81, 209–212 (1990). https://doi.org/10.1007/BF00230117
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DOI: https://doi.org/10.1007/BF00230117