An A112G MOPR knock-in mouse line was generated in the C57Bl/6 background by and propagated by heterozygote matings [for detailed description of generation of Oprm1tm1Jabl mice, see Mague et al. (2009)]. All mice (8 –15 weeks, 18 –30 g) were housed and maintained on a 12-h/12-h light/dark cycle with food and water available ad libitum. Animals were used in accordance with methods approved by University of Pennsylvania Animal Care and Use Committee.
