Cannabinoid CB2 Receptor: A New Target for Treatment of Cocaine Addiction

Cocaine addiction is a serious social and biomedical problem worldwide, and, so far, there is no effective medication available for clinic use. Given an important role of brain cannabinoid CB₁ receptor (CB₁R) in drug reward and addiction, the majority of cannabinoid-based medication development studies have focused on brain CB₁R. In addition to CB₁R, growing evidence suggests that CB₂R is also expressed in the brain, particularly in dopamine (DA) neurons in the ventral tegmental area (VTA). Activation of CB₂R inhibits VTA DA neuronal activities, DA release in the nucleus accumbens, and intravenous cocaine self-administration. Furthermore, chronic cocaine administration significantly upregulates neuronal CB₂R expression in the brain and in VTA DA neurons, suggesting that brain CB₂R may constitute a new therapeutic target in the treatment of cocaine addiction. In this chapter, we review the recent progress in brain CB₂R research, focusing on the role of brain CB₂R in drug abuse and addiction.