To determine whether dopamine receptor (DR) activation contributes to the modulation of γ oscillations by ethanol, we tested the roles of selective DR1/5 antagonists SCH23390 and DR2/3/4 antagonist raclopride. SCH23390 (10 μM) had no effect on γ power (108.4 ± 4.4% of baseline, P > 0.05 vs. control, n = 11, Figures 2A,B). Subsequent application of ethanol (50 mM) caused a small decrease in γ power (by 18.9 ± 4.1% compared to SCH23390 baseline, P < 0.05, n = 11, Figure 2A). This decrease was smaller than that induced by 50 mM ethanol alone (Student t-test P < 0.05). Application of 100 mM ethanol reduced γ power by 42.8 ± 4.9% (P < 0.01, n = 11). This reduction was not different from that of 100 mM ethanol alone. These results show that DR1/5 antagonist SCH23390 significantly reduced 50 mM but not 100 mM ethanol-induced suppression of γ oscillations.
