Figure 3
Application of TGOT reveals a population of AMPA-R miniature EPSCs with slow activation and deactivation kinetics. A: The histograms show the distribution of the decay time constants (τD) of miniature AMPA-R EPSCs pooled from 6 cells and detected during an identical time period of 5 minutes before (top, n = 1075 events) and after the application of 1 μM TGOT (bottom, n = 1563 events). In the presence of TGOT, the appearance of slowly decaying mEPSCs was noted in addition to the fast mEPSC population of mEPSCs with faster kinetics also found in the control situation. B: Averaged currents obtained from 91 individual mEPSCs of representative recorded neurons during TGOT treatment. Compared to the fast mEPSCs (upper trace), the averages of slow mEPSCs obtained in the presence of TGOT (lower trace) exhibited longer monoexponential constants for rise time (from τR = 0.5 ms in control to τR = 0.8 ms in TGOT) and decaying phases (from τD = 4.5 ms in control to τD= 8.0 ms in OT). The mean amplitude was also reduced in the presence of TGOT. C: Graph summarizing the changes observed in the mean amplitude (Amp.), rise time (τR), and decay time constants (τD) of AMPA-R mEPSCs during perfusion of TGOT. TGOT-induced increase in frequency was always associated with the appearance of slow rising and decaying currents having lower amplitudes. All changes observed during TGOT application were significant: p < 0.01 (**: τR, n = 6), and p < 0.001 (***: Amp and τD, n = 6) using the Student's t-test.