The effect of the KOR system in modulating ethanol effects on GABA transmission in CeA is summarized on Figure 5C,D. In control condition, ethanol alone increased IPSPs by 48%. In the presence of dynorphin or U69 the action of ethanol was diminished, increasing GABAergic transmission by 32% and 29% respectively. However, the ethanol effect was obliterated when neurons were pretreated with norBNI. The use of paired-pulse paradigms suggest that these effects took place at a presynaptic level. The paired pulse ratio was decreased by 34% with ethanol alone, 23% when ethanol was applied in the presence of dynorphin and 17% in the presence of U69, a range consistent with drug effects observed on IPSP amplitude.
