Figure 5

Alterations in NMDA receptor-mediated currents. Top panel. Representative traces of currents induced by 100 μM NMDA in the presence or absence of 50 μM Mg²⁺ at a holding potential of -70 mV. In the pan-neuronal model, the NMDA current in the absence of Mg²⁺ is smaller in the transgenic (Tg) cell while in the presence of Mg²⁺, the current is similar to the WT. In the striatal model, the NMDA current in the presence or absence of Mg²⁺ is larger in the transgenic cell than in the WT cell. In the cortical model NMDA currents in the presence or absence of Mg²⁺ were similar in WT and transgenic cells. 2^nd and 3^rd Panels. Graphs showing mean peak currents (± SEM) and mean peak current densities (± SEM) evoked by 100 μM NMDA in the absence of Mg²⁺ in each model. In the pan-neuronal model, NMDA peak currents were significantly smaller in transgenic cells at -70 and -40 mV and current densities were significantly smaller at -70 mV only. In contrast, in the striatal model, NMDA peak currents were significantly larger in transgenic cells at -70 and -40 mV and current densities were significantly larger at -70 mV only. In the cortical model, there were no differences in NMDA peak currents and current densities between WT and transgenic cells at any holding potential. Bottom Panel. Bar graphs showing mean percent block (± SEM) of NMDA currents by 50 μM Mg²⁺. In the pan-neuronal and striatal models, Mg²⁺ block was significantly smaller in transgenic compared to WT cells at -70 and -40 mV. In the cortical model, there were no differences in Mg²⁺ block between WT and transgenic cells at any holding potential.