Figure 5. Recruitment of AMPA receptors to the PSD increases quantal frequency but not amplitude.
A. mEPSCs were measured from the same dissociated hippocampal neuron (expressing GluA1-mCh-CIB and CRY2-GFP-homer1c) in the dark and 5 min following blue light exposure. Scale bar 10 pA/1 s.
B. mEPSC amplitude and frequency values measured in the dark and 6–8 min following blue light are plotted for dissociated hippocampal neurons expressing GluA1-mCh-CIB along with CRY2-GFP-homer1c (n=14 cells, frequency dark vs light, p= 0.028, amplitude dark vs light p= 0.18, paired Student’s t-test).
C. mEPSC amplitude and frequency normalized to their respective dark values are shown.
D. Cumulative distributions (250 events) of mEPSC frequency (inter-event interval, left panel) and amplitude (right panel) for a representative neuron expressing CRY2-GFP-homer1c and GluA1-mCh-CIB in the dark (red) and 6–8 min following light exposure (blue). Note the robust decrease in inter-event interval (p=0.004, Kolmogorov-Smirnov test), with no significant change in amplitude (p= 0.695, Kolmogorov-Smirnov test).
E. Normalized mEPSC frequency (left panel) and amplitude (right panel) values are plotted for cells where GluA1-mCh-CIB was recruited to different PSD scaffolds: PSD95-GFP-CRY2, CRY2-GFPPSD95FingR or CRY2-GFP-homer1c. Control cells expressed CRY2-GFP-homer1c and CIB-mCh instead of GluA1-mCh-CIB. mEPSC frequency and amplitude values were measured 6–8 min following light exposure and normalized to their respective dark baseline values. The number on each bar represents the number of cells recorded for each condition, ±SEM.
F. Average mEPSC frequency (open circles) and amplitude (filled circles) values (normalized to dark baseline values) are plotted as a function of time after blue light onset. mCh-GluA1-CIB was recruited to CRY2-GFP-homer1c for this experiment. Values represent averages from 6 neurons ±SEM. See also Fig. S2.