Fig. 1.

Increased AMPA mEPSC amplitudes in hippocampal neuron from SJ1-KO mice. (A) Typical mEPSC recordings from WT (Upper) and SJ1-KO (Lower) neurons [14 ays in vitro (DIV)]. (B) Cumulative distributions of mEPSC amplitudes for WT and SJ1-KO neurons revealing scaled-up amplitudes in SJ1-KO neurons. (C) Average mEPSC amplitudes are increased in SJ1-KO neurons. This increase results in an apparent increase in mEPSC frequency (D) due to a higher number of events above threshold. (E and F) No change in unit channel current of AMPA receptors (E), but an increase in the total number of open channels (F) in SJ1-KO cells as demonstrated by nonstationary fluctuation analysis. (G) Examples of whole-cell AMPA (downward deflections) and NMDA (upward deflections) currents evoked by fast application of 100 μM glutamate to WT and SJ1-KO cells. The currents were recorded in the presence of 500 nM TTX and 50 μM PTX. AMPA currents were recorded by blocking NMDA receptors with 50 μM APV at the holding potential of −60 mV. NMDA currents were recorded in the presence of 10 μM CNQX to block AMPA receptors and 20 μM glycine to activate NMDA receptors at the holding potential of +60 mV. (H) Statistical analysis showed that the ratio of AMPA/NMDA current is increased in SJ1-KO neurons.