OPRM1 and Wilson disease: Our group (Bajo et al., 2008, 2009) and others (Madhavan et al., 2010a; Meye et al., 2012) reported that acute morphine increases GABAergic transmission during spontaneously-morphine WD rats and naloxone-precipitated withdrawal combined with recordings without naloxone showed similar inverse effects of acute MOR agonists on GABAergic transmission during morphine withdrawal.