Corticotropin-releasing factor, neuroplasticity (sensitization), and alcoholism

Abstract

Sensitization is a ubiquitous biological phenomenon that has a role in the neuroadaptation of many different functions, from learning and memory to stress responsivity. Historically, a specific form of sensitization termed psychomotor sensitization (mistermed in my view as “behavioral sensitization”) is induced by repeated administration of drugs of abuse and has been linked to the neuroadaptive changes associated with increased drug-seeking behavior associated with addiction. Largely observed with psychostimulant drugs, psychomotor sensitization has been considered a model for the increased incentive salience contributing to the increased motivation to seek drugs in individuals with a previous history of drug use. Psychomotor sensitization also has been observed with repeated administration of ethanol in mice, but not in rats, and psychomotor sensitization to ethanol also has been linked to activation of both the hypothalamic-pituitary-adrenal (HPA) system and extrahypothalamic brain stress systems (Fig. 1). However, the exact mechanism for stress-induced sensitization has remained elusive.