Figure 4.
The plant-derived cannabinoid receptor agonist Δ9-THC inhibits glutamate release through activation of CB1Rs in SD rat hippocampal brain slices. Top, Traces showing the effect of Δ9-THC on mean fEPSPs in rat hippocampal slices in control aCSF (gray line, left) and following treatment with the CB1R antagonist AM251 (1 μm, gray line at right) in a different rat hippocampal slice. Bottom, Mean time course comparing the effects of Δ9-THC (10 μm) to those of RAMEB alone and to Δ9-THC (10 μm) after a 20 min treatment with AM251 (1 μm). Note that whereas RAMEB alone significantly inhibited glutamate release, the effect of Δ9-THC in the same concentration of vehicle was significantly larger (**p < 0.01, RM-ANOVA). Furthermore, the effect of Δ9-THC on fEPSPs was not significantly different from RAMEB alone, when slices were pretreated with AM251 (p > 0.05, RM-ANOVA).