Excitatory postsynaptic currents in neurones of the central nervous system have a dual-component time course that results from the co-activation of AMPA/kainate-type and NMDA-type glutamate receptors. New approaches in electrophysiology and molecular biology have provided a better understanding of the factors that determine the kinetics of excitatory postsynaptic currents. Recent studies suggest that the time course of neurotransmitter concentration in the synaptic cleft, the gating properties of the native channels, and the glutamate receptor subunit composition all appear to be important factors.