There have been several studies (Barr et al., 2007; Vallender, Rüedi-Bettschen, Miller, & Platt, 2010; Ramchandani et al., 2011; Bilbao et al., 2015; Henderson-Redmond, Lowe, Tian, & Morgan, 2018) examining the functional consequence of ethanol application on neurons carrying MOR N40D allelic variants. This has mainly been done in primates, rodent overexpression models, or MOR humanized mice harboring MOR N40D (Bilbao et al., 2015). However, no functional or electrophysiological analyses on ethanol-treated human cultured GABAergic neurons carrying MOR genetic variants have been reported. To determine whether N40 and D40 AD-iNs respond differently to acute application, we perfused cultures with HEPES-based recording solution supplemented with 40 mM ethanol. Recordings were performed in voltage-clamp, and the AMPA/kainate receptor antagonist CNQX (20 μM) was perfused into the bath for all recordings to isolate the true inhibitory postsynaptic current (IPSC). Furthermore, this allowed us to clamp the AD-iNs at −70 mV rather than 0 mV. Spontaneous inhibitory postsynaptic currents (sIPSCs) were monitored for 5 min prior to ethanol application to measure the baseline responses in both N40 and D40 AD-iNs (Control, Fig. 3A). Following
