Interoception and alcohol addiction: Vagotomy induces long-lasting suppression of relapse-type behavior

Drug addictions are chronic mental disorders characterized by compulsive drug seeking and drug use, despite their negative consequences. It is a priority to find therapeutic alternatives to prevent relapse, as there are still no treatments that can ensure abstinence. One of the neural systems implicated in the appearance of the states of discomfort that motivate relapse is the interoceptive system, which oversees our internal body states. However, less attention has been given to the peripheral components of the interoceptive system and their role in addictions. Within these pathways, the vagus nerve represents one of the main visceral afferents of the interoceptive system. We hypothesized that the interruption of visceral afferent pathways would decrease the motivational effects of the drug, thereby either decreasing or preventing drug cravings. To test this idea, we used rats of a high-alcohol-drinking line and measured the effect that vagus nerve resection had on the relapse-like alcohol drinking, expressed as the alcohol deprivation effect, a phenomenon that has been linked to addiction-related events such as alcohol cravings. We found that even though vagotomy completely eliminates the effect of alcohol deprivation, it has no impact on water consumption or animal weight. These results give us valuable information about the relationship between the autonomic nervous system and alcohol use disorders and allow us to propose new clinical research that might have translational options.