Fig. 5.

Reduction of NMDA-receptor-mediated currents is independent of the presence of α-neurexins on presynaptic inputs. The use-dependent induction of the NMDA-receptor impairment was studied in neocortical slice cultures with integrated GFP-expressing WT neurons, as characterized in Fig. 4. (A) Superimposed traces of spontaneous miniature synaptic responses recorded in Mg²⁺-free medium from GFP-positive neurons grown on neocortical slices from control SKO or TKO. Arrows indicate time point at which the amplitude of NMDA-receptor currents was measured (20 ms after rise time). (B) Scatter diagram of the ratio of NMDA- to AMPA-receptor-dependent currents in miniresponses recorded from WT GFP-positive neurons grown on SKO and TKO slices. (C) Average NMDA- to AMPA-receptor-dependent current ratios obtained from B. (D–F) Same as A–C, except that the recordings were obtained in GFP-negative neurons in slices from SKO and TKO mice to confirm the presence of the NMDA-receptor phenotype in the cocultured slice neurons (compare to Fig. 1E). Data shown are means ± SEM (n.s., not significant; ^*, P < 0.05).