Fig. 4.

Phorbol 12-myristate 13-acetate (PMA) but not Gö6976 reduces ethanol (EtOH) excitation. Pooled results from recordings of pDAergic ventral tegmental area (VTA) neurons tested with EtOH (25, 40, and 80 mM). For each neuron, each concentration of EtOH was applied in the extracellular medium for 6 minutes and washed out for at least 10 minutes before the next concentration of EtOH was tested. Recordings were made with normal saline alone or normal saline containing either PMA (1 μM), Gö6976 (10 μM), or both drugs, in the recording pipette. In recordings with electrodes containing saline alone (▪), or saline with PMA plus Gö6976 (∇), or saline with Gö6976 alone (○), the excitatory effects of EtOH were not statistically different; in recordings with PMA (▼) alone in the pipette, the effect of EtOH was attenuated compared with all the other groups (2-way ANOVA, F(3, 109) = 13.6, p < 0.05; p < 0.05 for difference between PMA and all other conditions, p > 0.05 for comparisons among all other conditions). Also plotted are data from Fig. 3 of the excitatory effect of 80 mM EtOH after the 40-minute administration of dopamine (◊).