We assessed corticosterone, proopiomelanocortin (POMC), β-endorphin, CART 55–102 levels in plasma (by ELISA), along with mRNA levels for D2 dopaminergic receptor (D2R), κ-receptor (KOR), orexin 1 receptor (OX1R), CART 55–102, and potential markers of cocaine abuse: miRNA-124 and miRNA-137 levels in the PFC (by PCR). This evidence concerns the gene OPRK1 and cocaine abuse.