Voltage sensitivity of NMDA-receptor mediated postsynaptic currents

✍ Scribed by A. Konnerth; B. U. Keller; K. Ballanyi; Y. Yaari

• Book ID: 104673966
• Publisher: Springer-Verlag
• Year: 1990
• Tongue: English
• Weight: 453 KB
• Volume: 81
• Category: Article
• ISSN: 0014-4819
• DOI: 10.1007/bf00230117

✦ Synopsis

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.