Drug addiction

Drug addiction is a pervasive worldwide problem characterized by compulsive drug use that continues despite negative consequences and treatment attempts. Historically, the biological basis of drug addiction has focused principally on neuronal activity. However, despite their pivotal role in the underlying pathology of drug addiction, neurons are not the only central nervous system (CNS) component involved. The role of additional cell types, especially the CNS immunocompetent microglial cells, in the development of tolerance and related neuroplastic changes during drug taking, addiction, and withdrawal is also emerging. Within this perspective, this chapter reviews the roles of microglial cells in several aspects of drug addiction and its behavioural consequences, including reward, tolerance, dependence, and withdrawal. The cellular and molecular mechanisms which are particularly recruited will be emphasized. Lastly, we will also summarize the development of pharmacological modulators of microglial activation that offer novel treatment strategies and highlight the need to better understand the roles of microglia in the context of drug addiction.Xiaohui Wang, Thomas A. Cochran, Mark R. Hutchinson, Hang Yin, and Linda R. Watkin