Fig. 1

The biophysical and pharmacological properties of AMPAR- and NMDAR-mediated synaptic responses in lamina II neurons do not change across early postnatal development. (A) Averaged mEPSC traces of lamina II neurons (n = 62) at both − 60 mV (gold) and + 60 mV (black) from early postnatal (P7-P21) male rats. (B) Ratio of mEPSC peak amplitude at − 60 mV versus peak amplitude at + 60 mV (at 20 ms from onset) from lamina II neurons of postnatal rats aged P7 to P11 (black, n = 22 neurons), P12 to P16 (teal, n = 19 neurons), and P17 to P21 (aqua, n = 21 neurons) (C) Averaged mEPSC traces at + 60 mV for rats and neurons in the same postnatal age bins described in B. (D) Charge transfer through the NMDAR component of mEPSCs at + 60 mV (from 20 to 500 ms). (E) The exponential decay constants measured from mEPSCs at + 60 mV. (F) Averaged mEPSCs at + 60 mV before (black) and after (red) application of the GluN2B antagonist, 1 uM Ro25–6981 (n = 13). Inset, Ro25–6981-sensitive NMDAR mEPSC difference current. (G) Averaged mEPSCs at + 60 mV before (black) and after (green) application of the GluN2A antagonist, 10 uM TCN-201 (n = 14). Inset, TCN-201-sensitive mEPSC difference current. (H) The percent reduction in NMDAR charge transfer by both 1 uM Ro25–6981 (red, left bars) and 10 uM TCN-201 (green, right bars) were not significantly different across the various developmental time points: P7-P11 (n = 4,5), P12-P16 (n = 5,5), P17–21 (n = 4,4). (I) Averaged NMDAR mEPSCs before (black) and after (blue) application of 10 uM DQP-1105 (n = 14). Inset, 10 uM DQP-1105-sensitive NMDAR mEPSC difference current. (J) Percent NMDAR charge transfer reduction produced by administration of 1 uM Ro25–6981 (red, n = 13), 10 uM TCN-201 (green, n = 14) or 10 uM DQP-1105 (blue, n = 14). Cells with a negative blockade reflect an antagonist-independent run-up in NMDAR charge transfer [12] during the course of recording. All traces are presented as mean (darker line) +/− standard error (lighter shaded area). Scale bar x axes = 100 ms, y axes = 5 pA