As predicted (Long et al., 2009), JZL184 decreased VE-822 concentration core temperature across time (Figure 7D; F(3,34) = 2.63, p < 0.01). To definitively test whether JZL184 increases 2AG levels during reward seeking, we assessed lipid content in VTA tissue from JZL184 and vehicle-treated

rats upon completion of the ICSS-VTO task and found that JZL184 significantly increased 2AG VTA tissue content in comparison to vehicle (Figure 7E; t(27) = 2.07, p = 0.048), thereby confirming that JZL184 augments 2AG levels in the VTA during reward directed behavior in the rat. To assess the effects of increasing 2AG levels on the neural mechanisms of reward seeking we treated rats with JZL184 (10 mg/kg i.v.) while responding was maintained by brain stimulation reward in the ICSS-VTO task. As observed using a cumulative dosing approach, JZL184 Selleckchem Torin 1 (10mg/kg i.v.) decreased response latency (Figure 8A; t(14) = 2.36, p = 0.033; mean values: b = 3.55, v = 3.48, JZL = 2.89 s). Enhanced reward seeking occurred in parallel with an increase in cue-evoked

dopamine concentration ( Figure 8B; F(2,14) = 10.86 p < 0.01; 10 mg/kg versus vehicle, p < 0.01; also see Figure S3B for mean dopamine concentration traces). The effect of JZL184 on dopamine signaling during individual trials is illustrated by the representative color plots and accompanying dopamine concentration traces ( Figure 8C), while the effect of JZL184 on dopamine signaling across trials is shown by the representative surface plot ( Figure 8D). To confirm that 2AG levels within the VTA are alone sufficient to facilitate the neural mechanisms of reward seeking, we infused JZL184 into the VTA while measuring dopamine concentrations and behavior maintained in the ICSS-VTO task. Although the required vehicle to achieve solubility (a 6 μg/0.5 μl solution required 100% dimethyl sulfoxide [DMSO]) increased response latency; remarkably, intrategmental JZL184 (6 μg, ipsilateral) reversed the DMSO-induced deficits in

reward seeking ( Figure 8E; t(6) = −2.51, p = 0.046; mean values: b = 3.75, DMSO = 4.61, JZL = 3.47 s) while increasing cue-evoked dopamine concentrations ( Figure 8F; F(2,18) = crotamiton 10.84 p < 0.01; 6 μg versus vehicle, p = 0.023). To verify that the effects of intrategmental JZL184 on reward seeking were CB1 receptor dependent, we then treated rats with a subthreshold dose of rimonabant (1.25 mg/kg i.v.), which reverted response latencies to DMSO conditions. The effects of intrategmental DMSO and JZL184 on cue evoked dopamine events occurring in individual trials are illustrated by the representative traces in Figure 8G, whereas the effects across trials are depicted in a representative surface plot ( Figure S4C). JZL184-induced increases in cue-evoked dopamine concentration and reward seeking can also be observed by viewing audio-visual material ( Movie S3).