Fig. 3.
Current–voltage and pharmacological characterization of excitatory synaptic inputs to cholinergic cells.A, A series of EPSCs evoked by intrastriatal stimulation after blockade of NMDA and GABAA receptors at holding potentials between −105 to +35 mV. Vertical arrows inA and C indicate the stimulus artifact.B, Current–voltage plot for the same cell inA revealed a reversal potential of approximately −5 mV. Each point is the mean peak amplitude of three EPSCs evoked at each of the holding potentials. C, At −65 mV, bath application of DNQX (20 μm) completely blocked the evoked inward current. Traces are averages of 25–30 individual trials. D, Time series for the effect of bath application of DNQX on evoked EPSC amplitude from the same cell inC (open circles, individual EPSCs;filled circles, mean ± SD of six sequential EPSCs). These data illustrate that intrastriatal stimulation in the presence of APV and BMI evokes a solely AMPA receptor-mediated inward current.