Nandrolone alters the behavioral response to cocaine as well as striatal and cortical dopamine receptors of prepubertal male rats

Nandrolone, is an anabolic androgenic steroid (AAS) used by adolescents and young adults. Supraphysiologic doses of AAS are correlated with dysfunctions in anxiety and reward. This study examined whether exposure to nandrolone before puberty altered anxiety- and addictive-like behaviors. Dopamine type 2 receptors (D2DR) in the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC) were also analyzed. Beginning on day 28 and ending on day 37, male rats received a daily injection of nandrolone decanoate (20 mg/kg) and were subsequently evaluated for anxiety. Their locomotor response (sensitization) and preference (conditioned place preference (CPP) to cocaine (15 mg/kg) were also assessed. Nandrolone reduced anxiety and ambulation, accelerated the development of sensitization to cocaine, and reduced CPP to cocaine by 27%. Expression of D2DR in the NAc and the PFC of males was increased by nandrolone, whereas treatment with cocaine reduced accumbal D2DR. We hypothesize that nandrolone accelerated the development of the neural circuitry that participates in behavioral sensitization and reduced the rewarding properties of cocaine. The observed increase in accumbal D2DR may have potentially mediated the reduction in anxiety and ambulation and hastened the maturation of the neural circuitry responsible for the sensitized response to cocaine.