Figure 5.

Evoked and spontaneous LGC-53 currents from striatal slices. A, Lentiviral injections into the dorsal striatum produced restricted expression in dorsolateral striatum. Scale bar, 500 μm. B, High-magnification image of transduced and nontransduced neurons in a field from the dorsolateral striatum. Whole-cell recording pipette (dashed outline) and field stimulation pipette (solid outline) are evident in the right. Scale bar, 25 μm. C, Recordings at the indicated membrane potentials from a nontransduced striatal neuron, as identified by Venus fluorescence. The red trace shows the response at +20 mV in the presence of 1 μm NBQX, 50 μm d-APV, and 5 μm gabazine. Stimulus artifacts in this and the subsequent figures have been blanked for clarity. D, In a transduced neuron, antagonist application revealed a residual current. Inset, Scaled traces showing that the residual current has a slower rise to peak than the peak-scaled mixed glutamate/GABA IPSC. E, F, Current–voltage characteristics of the antagonist-insensitive, residual PSCs mirror those in transfected cultures (Fig. 1), including the unique permeability to methanesulfonate (MeS). Curves in D represent PSCs normalized to responses at +30 mV [gluconate (Gluc) and MeS responses] or −90 mV (chloride responses). G, H, Effects of the DA transport inhibitor GBR12909 (1 μm) on residual evoked PSCs. *p < 0.05. I, J, Spontaneous LGC-53-mediated transmission. I1, Total spontaneous PSCs from a transduced neuron before wash in of NBQX, d-APV, and gabazine. I2, In the presence of antagonists, infrequent events remained (boxed events shown at higher resolution in I2). J, In a nontransduced neuron, all events were eliminated by antagonists. For summary data, see Results.