A, recordings from a ventral interneuron in CNQX-treated culture (left) show very intense spontaneous activity; PSCs comprise only fast decay events (middle, superimposed traces; right, average response), with τ of 2.6 ms and a rise time of 0.8 ms, measured as in Fig. 1 B,. block of AMPA/kainate receptors by CNQX (left, same cell as in A) fully abolished fast PSCs and unmasked slow τ events; middle, single events are superimposed, and kinetics are measured from the average PSC (right, τ = 29 ms, rise time = 1.6 ms). C, DRG stimulations evoke polysynaptic currents in the patched ventral interneuron. Evoked currents in standard Krebs solution (left) appear reduced (by 41 %) in area after the application of CPP (right); each trace (left and right) represents the average of 5 consecutive evoked PSCs (different cell from A and B).