Results of a recent study in an animal model of cocaine addiction show that paternal cocaine self-administration caused epigenetic changes (i.e., changes in the patterns of gene expression independent of gene mutations) in sperm cells that resulted in an altered response to cocaine in the male (but not in the female) offspring. Specifically, the male offspring of sires (rat fathers) that self-administered cocaine did not work as hard as controls to receive infusions of cocaine, a finding that suggests they inherited a decreased reinforcing effectiveness of cocaine. The intergenerational behavioral effect uncovered in this study appears to be mediated, at least in part, by the epigenetic upregulation of Bdnf gene expression in the medial prefrontal cortex. Thus, cocaine reprograms the male germline through an epigenetic mechanism (acetylation) resulting in the inheritance of an abnormal reward circuitry.(Vassoler et al, 2013)
Vassoler FM, White SL, Schmidt HD, Sadri-Vakili G, Pierce RC (2013). Epigenetic inheritance of a cocaine-resistance phenotype. Nat Neurosci 16(1): 42-47.