endogenous opioids. We have briefly examined this but failed to detect any endogenous opioids in our cultures. These data may ultimately help predict altered ethanol sensitivity and/or dependence for individuals who carry MOR N40D allelic variants. Finally, opioid receptors have recently been shown to be diffusely distributed and laterally mobile on the axon surface (Jullié et al., 2020), and the D40 variant could impact the lateral mobility of the receptor. Thus, an interaction of MOR with GABAA receptors (or possibly GABAB) could impact the gating and conductance of the channel. This is entirely speculative and needs to be tested experimentally.
