Figure 1.

Effects of maternal immune activation (MIA) and adolescent Δ⁹-tetrahydrocannabinol (THC) administration on ventral tegmental area (VTA) dopamine neuron activity in vivo. Adolescent THC administration prevented the Poly I:C-induced decrease in the number of spontaneously active VTA dopamine neurons (A) but not the decrease in firing rate (B). Graphs show the effect of poly IC and THC (or vehicles) in the percentage of spikes in burst (C), mean burst duration (D), mean number of spikes in bursts (E) and intra-burst frequency (F). Superimposed colored diamonds show the averages for each individual rat. Both Poly I:C and THC, or their combination, induced a reduction in the percentage of spikes in bursts (C), whereas THC prevented alterations induced by Poly I:C in the other electrophysiological parameters (D,E). The number of cells for each group is: veh-veh, n = 156; Poly I:C-veh, n = 121; veh-THC, n = 101; Poly I:C-THC, n = 117. The horizontal blue line represents the mean. Statistical analysis was conducted with two-way ANOVA (Poly I:C and THC treatments as factors) and Sidak’s multiple comparison test. Asterisks on graphs represent the result of the Sidak’s multiple comparison test: *P < 0.05, **P < 0.01, ***P < 0.001.