Fig. 2.

Synaptic currents evoked by local stimulation.A, At a holding potential of −50 mV, single shock bipolar electrical stimulation evoked a fast inward current that was blocked by CNQX (10 μm) and dl-AP-5 (100 μm) and a slower outward current. Eachtrace is preceded by a 10 mV hyperpolarizing step of 10 msec duration to monitor input conductance and changes in access resistance. B, Time course from a single experiment showing the reversible block of outward synaptic potential by the GABA_A antagonist bicuculline (10 μm) applied to the superfusion medium for the period indicated by the bar. Each point represents the average of four traces evoked every 15 sec.C, The outward current reversed polarity at −69 mV, close to E_Cl.