For electrophysiological and qPCR analyses we employed at least 3 independent infection batches of iNs (biological replicates). The effects of MOR agonists (DAMGO or morphine) were normalized to basal activity in the absence of the drugs, i.e. drug effects are defined as the relative changes to the baseline values (in the absence of drug). The effect of drugs before and after the application in the same group of cells were compared using paired t-tests. On normalized post-treatment data, 1-way ANOVA tests were used to evaluate the effects between genotypes.
