D4 receptors reduce GABAAR currents and surface
expression in PFC pyramidal neurons. A, plot of normalized peak
GABA (50 μm)-evoked current as a function of time in the absence
and presence of D4 agonist (PD168077, 30 μm)
application in dissociated PFC pyramidal neurons. Inset,
representative current traces (at time points denoted by #). Scale
bar, 500 pA, 1 s. B, plot of normalized evoked IPSC as a
function of time and agonist application in PFC slices. Inset,
representative IPSC traces (at time points denoted by #). Scale bar,
25 pA, 20 ms. C, cumulative plot of the distribution of mIPSC
amplitudes before (control) and after PD168077 application in a cultured PFC
pyramidal neuron. Inset, representative mIPSC traces. Scale
bar, 50 pA, 2 s. D, immunocytochemical images of surface
GABAAR β2/3 subunits and MAP2 staining in PFC cultures either
untreated (control) or treated with PD168077 (30 μm, 10 min).
E, quantitative analysis of surface GABAAR β2/3
clusters along the dendrites (density, size, and normalized intensity) in
control versus PD168077-treated neurons. *, p < 0.05,
ANOVA. ctl or con, control; PD,. PD168077.