We focused our electrophysiological studies on the BLA given the high level of both DAGL∝ and CB1 receptor expression in this subregion (Katona et al, 2001). Schematic diagram of recording sites and stimulation sites within the BLA are shown in Figure 4a. Recordings were restricted to the magnocellular division of the BLA. A representative biocytin filled neuron typical of cells used for electrophysiological recordings is shown in Figure 4b. We first examined the ability of BLA principal neurons to engage in eCB-mediated suppression of GABAergic transmission. Earlier data from isolated neurons and brain slices from postnatal rats indicate that eCB signaling mediates DSI in the BLA (Zhu and Lovinger, 2005), as it does in numerous other brain regions (Kano et al, 2009). Consistent with these data we found that postsynaptic depolarization from −70 to 0 mV for 5 s produced DSI, reducing the IPSC amplitude to 80.1 ± 5.1% of control (p < 0.001, N = 12; Figure 4c), which recovered to baseline by 30 s.
