Our study provides experimental evidence describing the functional consequences of the MOR N40D SNP on ethanol sensitivity in human neuronal context, and this preparation permits the study of synaptic modulations that may be involved in the pathogeneses of AUDs. We hypothesized that GABAergic human neurons expressing MOR N40D genetic variants would display differential sensitivities to ethanol that would depend on time and concentration of ethanol exposure. First, we generated AD-iN cells from isogenic stem cell lines harboring either MOR N40 or D40 genetic variants. Second, we demonstrated that isogenic AD-iN cells express the appropriate inhibitory neuronal marker (Fig. 1) and develop a similar number of synapses between MOR N40 and D40 iNs (Figs. 1 and 2). Third, we demonstrated that acute application of ethanol caused an increase in excitability and synaptic release, which was observed exclusively in N40 iNs (Figs. 3 and 4). The increase in the frequency of mIPSCs suggests that acute ethanol application impacts presynaptic GABAergic terminals in iNs expressing the MOR N40 genetic variant, with no effect on amplitude (Fig. 4). Finally, a CIE exposure paradigm for
