Figure 1.

Developmental changes in the subunit composition of NMDARs and neuronal circuit activity in hippocampal culture. A, Ifenprodil-sensitive NMDAR currents. To determine the proportion of ifenprodil-sensitive currents, whole-cell currents mediated by NMDARs were recorded without drugs and with the sequential addition of ifenprodil and APV (n = 5). B, Firing rate in hippocampal pyramidal neurons. Spontaneous neuronal firings were monitored by the cell-attached mode of patch-clamp recording for 3 min (n = 4 series of experiments). C, Neuronal density in culture. Neuronal densities were obtained by counting Hoechst 33258 and MAP2 double-positive cells over 10 objective fields (0.15 mm²) in each series of culture. Mean data are plotted from four independent series of culture.