Fig. 4.

Synaptic activity sustains and potentiates E2 effects. (A) Schematic of combined E2 and NMDAR activation experiments. Neurons were treated with E2 for 0, 30, or 60 min; for 30 min with E2 followed by activation of NMDAR for 30 min; or activation of NMDAR alone for 30 min. (B) Effect of E2 priming on dendritic morphology; cells were treated as described in A. (C) Surface staining of GluR1 (n-GluR1) after treatments as in A. The total number of n-GluR1 puncta was measured; n-GluR1 levels are significantly greater than control after combined E2 and NMDAR activity (blue bar). (D) Electrophysiological recording of AMPAR mEPSCs after treatments. Frequency of AMPAR mEPSC events are significantly greater than controls with combined E2 and NMDAR activation (blue bars). AMPAR amplitudes are also increased with treatment with E2 followed by NMDAR activation, but not significantly. **, P < 0.005; ***, P < 0.001; #, different subgroup of significance according to Tukey B post hoc analysis. (Scale bar, 5 μm.)