Electrophysiological Investigation of NMDA Current Properties in Brain Slices

Analysis of electrophysiological properties of NMDARs and NMDAR-mediated synaptic transmission in identified neurons and synapses in brain slices is a major step in understanding their function in normal and pathological neuronal brain networks. In many central synapses excitatory postsynaptic currents (EPSCs) are mediated by excitatory neurotransmitter glutamate that activates colocalized AMPAR and NMDAR generating a complex EPSC. Here, we describe the methods commonly used in brain slices to study the electrophysiological properties of NMDAR-mediated component of spontaneous or evoked EPSCs by extracellular stimulation or by stimulating synaptically connected neurons. This approach is based on whole-cell patch-clamp recordings, pharmacological tools, and the analysis of the difference in temporal parameters between the AMPA and NMDA receptors. It allows pinpointing of the basic functional properties of NMDARs that are specific to identified brain regions, neurons, and synapses of wild-type or genetically manipulated mice.