Figure 3.
Synaptically evoked retrograde inhibition in SCs. Experiments were performed with a K-based internal solution. PF EPSCs were evoked at 0.5 Hz. At time t = 0, PF EPSPs were evoked with 10 stimuli at 50 Hz in current clamp. Recordings were then returned to voltage clamp, and EPSCs were evoked with 0.5 Hz stimulation. A, SSE in a representative experiment, with the response evoked by the conditioning train (left) and the average synaptic response recorded before and after the conditioning train (right). B, Time course of SSE in control conditions and in the presence of AM251. C, SSE (measured as EPSC amplitude at Δt = 3 s, normalized to EPSC before burst) in PCs and SCs recorded in control conditions, in the presence of AM251 in the bath, in the presence of the calcium buffer BAPTA (20 mm) in the recording pipette, in the presence of the DAG lipase inhibitor THL (2 μm) in the pipette, and in the presence of the DAG lipase inhibitor RHC 80267 (30 μm) in the bath. The number of experiments is indicated. All treatments led to a significant reduction of SSE for both SCs and PCs (p < 0.01; unpaired Student's t test). D, SSE at the PF to SC synapse in CB1R knock-out mice was significantly reduced compared with SSE at synapses in wild-type littermates (p < 0.01; unpaired Student's t test). norm., Normalized.
