Whole brain methionine-enkephalin of ethanol-avoiding and ethanol-preferring c57BL mice

These experiments systematically investigated ethanol preference in both the C57Bl/6N and C57Bl/6J mice utilizing three-choice 2-bottle preference test. In addition, these sublines were evaluated for whole brain methionine-enkephalin levels, which were significantly lower in C57Bl/6J mice (alcohol preferring) compared to C57Bl/6N mice (alcohol non-preferring). This finding supports the involvement of the peptidyl opiates in ethanol seeking behavior.