Early avoidance of a heroin-paired taste-cue and subsequent addiction-like behavior in rats

• Rats suppress intake of a saccharin taste cue when it is paired with heroin self-administration.
• Some rats suppress intake significantly more than others.
• Rats that most greatly suppress intake of the heroin-paired taste cue later evidence the greatest addiction-like behavior for heroin.
• β-catenin expression is decreased in the hippocampus of heroin self-administering animals.
• β-catenin, and NCS-1 expression are altered in the PFC in largest vs. smallest suppressors of saccharin intake.

The ability to predict individual vulnerability to substance abuse would allow for a better understanding of the progression of the disease and development of better methods for prevention and/or early intervention. Here we use drug-induced devaluation of a saccharin cue in an effort to predict later addiction-like behavior in a model akin to that used by Deroche-Gamonet et al. (2004) and seek to link such vulnerability to changes in expression of various mu opioid receptor and D2 receptor-interacting proteins in brain. The results show that the greatest heroin-induced suppression of intake of a saccharin cue is associated with the greatest vulnerability to later addiction-like behavior and to differences in the expression of WLS, β-catenin, and NCS-1 in brain compared to rats that exhibited the least suppression of intake of the heroin-paired cue and/or saline controls. Finally, because the self-administration model employed produced no significant differences in drug intake between groups, overall, the resultant changes in protein expression can be more closely linked to individual differences in motivation for drug.