Infusion of WIN 55212-2 within the BNST inhibits the excitatory drive from the infralimbic cortex to VTA dopaminergic neurons. A, Diagram of the stimulation, microinfusion, and recording protocol used in this experiment. Here, the IL was stimulated with a 100-pulse train and WIN 55212-2 (WIN, 500 μm) was microinfused within the BNST in a total volume of 100 nl >45 s. B, PSTHs showing ILCx-evoked responses before and during WIN 55212-2 infusion within the BNST on a VTA DA neuron. C–E, Graphs illustrating the effects of microinjection of WIN 55212-2 within the BNST (black bars) on excitation (C) obtained after stimulation of the ILCx and on basal activity parameters (D, E). Microinjection of WIN 55212-2 within the BNST prevented the short latency activation of VTA DA neurons evoked by ILCx stimulation but had no effect on the basal firing rate or bursting activity. Scores are percentages ±SEM of baseline response magnitudes (C) or basal activity parameters (D, E) for VTA DA neuronal responses evoked by ILCx electrical stimulation during microinjection into the BNST of VEH (white bars) or WIN 55212-2 (black bars). Numbers of neurons recorded in each group are mentioned in parentheses above each histogram bar. A two-tailed paired Student's t tests was performed for excitatory response, firing rate, and bursting activity. ***p < 0.001. REC, Recording electrode.