The sigma-1 receptor as key common factor in cocaine and food seeking behaviors

Abstract

Addiction and eating disorders involve brain reward circuits. A previous history of binge eating predisposes to addictive behavior, while the cessation of exposure to drugs of abuse leads to reward activities, including intake of tasty foods. Cocaine use is associated with a decrease in food intake, with reversal after the drug use is stopped. Exciting new findings show that receptors for the 'hunger' hormone, ghrelin, directly interact with the sigma-1 receptors (1R), which is a target of cocaine. 1R are key players in regulating dopaminergic neurotransmission and ghrelin-mediated actions. This review focuses on the 1 receptor as general neuroendocrine regulator by directly interacting with neuronal G-protein-coupled receptors. This review also covers the early mechanisms by which cocaine binding to 1 blocks the food-seeking behavior triggered by ghrelin. Such new findings appear as fundamental to understand common mechanisms in drug addiction and eating disorders.