Fig. 7. Effect of time in culture on responses of NMDA-gated currents to ifenprodil in cultured cortical neurons. (A ) Responses of NMDA-gated currents to 10 μm ifenprodil in HEK 293 cells expressing NR1–1a + NR2A (1a + 2A; n = 6) and NR1–1a + NR2B (1a + 2B; n = 9) receptors (Student t test, P < 0.001). ***P < 0.001. (B ) Percent inhibition of steady state NMDA-gated currents by 10 μm ifenprodil in neurons cultured for 1–4 weeks with a significant linear trend (P < 0.05). The n is 5 for 1, 3, and 4 weeks; 7 for 2 weeks. (C and D ) Illustrations showing inhibitory effect of ifenprodil on NMDA-gated currents in two neurons cultured for 1 week (C ) or 4 weeks (D ).