Fig. 2.

NMDA current is decreased at puberty in CA1 hippocampal pyramidal cells: reversal by THP. (A) (Left) Representative traces, evoked (100 μA) NMDA current (0.05 Hz; Pre-pub, above; Pub, below) recorded at −60 mV. Scale, 15 pA, 100 ms. (Right) 300 μA stimulation; Pub +/+, above; Pub δ−/−, below. Scale for +/+, 20 pA, 100 ms; for −/−, 20 pA, 250 ms. Amplitudes decreased at puberty, but were restored by THP and δ knock-out. (B) NMDA EPSC amplitude with increasing stimulation intensities (Pre-pub, black squares; +THP, open squares; Pub, black triangle; +THP, open triangle; Pub δ−/−, orange; +THP, blue). *P < 0.05, Pre-pub versus Pub. Error bars indicate SE of the mean. (C to F) Representative traces [(C) and (E)] and summary data [(D) and (F)] of evoked EPSPs (whole-cell current clamp, black; +THP, red) and NMDA EPSPs (blue; +THP, yellow). Scale, 1mV, 100 ms. With synaptic GABAergic current blockade [200 nM SR95531 (13), (C) and (D)], the NMDA/AMPA ratio was reduced at puberty (*P < 0.05 versus all other groups, **P < 0.05 versus pre-Pub, Pub). (E and F) Complete GABAR blockade. (G) Representative EPSC responses to paired stimuli were unaltered across groups. (H) Summary, paired pulse ratio. Scale, 50 pA, 100 ms.