Similar results were obtained with application of 0.5–1 μM U69. Superfusion of 0.5 μM U69 decreased IPSPs to 81 ± 6% of control and subsequent addition of 44 mM ethanol reversed the effect of U69, increasing IPSPs to 105 ± 7% of pre-U69 level (n = 4). Superfusion of 1 μM U69 decreased IPSPs to 77 ± 6% of control. Subsequent addition of 44 mM ethanol reversed the U69 effect and increased IPSP amplitude to 99 ± 9% of pre-U69 level (n = 4). Combining the data, U69 (0.5–1 μM) significantly decreased IPSPs to 78 ± 5% of control (n = 8; F(2,7) = 10.31). Subsequent addition of ethanol significantly increased IPSPs to 100 ± 7% of pre-U69 level (n = 8; Fig. 3C), reversing the U69 effect. The net ethanol effect relative to U69 levels was a 29 ± 7% increase of IPSP amplitude, an effect significantly dampened from the effect of ethanol alone (unpaired t-test: t = 2.186, df = 14). Also, the paired-pulse ratio was increased to 125 ± 9% of control value by U69 then reversed
