Impact of social environment on alcohol‐induced behavior

Abstract

Alcohol consumption occurring in social or solitary settings often yield different behavioral responses. For example, drinking of alcoholic beverages in a social setting is associated with enhanced positive effects including euphoria and increased sociality while drinking in a solitary setting is linked to augmented negative effects such as depressive symptoms and anxiety. The neurobiological mechanism by which the social environment impacts on behavioral responses to alcohol, however, remains understudied. Using the Drosophilamodel, we investigated whether distinct social environments affect behavioral responses to ethanol. In this study, we focused on the hyper‐locomotor activity that is typically used as a proxy for euphoria induced by ethanol. Wild‐type Canton‐S (CS) flies were exposed to ethanol in either socially‐isolated (1 fly per chamber) or socially‐enriched (13 flies per chamber) settings and their locomotor activities were analyzed. We found that the socially‐enriched flies showed significantly more hyperactivity under the influence of ethanol compared to the singly exposed flies. This suggests that the presence of other flies amplifies ethanol‐induced euphoria. Dopamine is known to be important for social interactions thus we explored the role of dopamine in the social effect on the ethanol response by examining the dopamine transporter mutant fumin with hyperdopaminergic tone. When exposed to ethanol in a social setting, fuminmutants showed the augmented hyperactivity compared to the singly exposed fumin as well as single‐ and group‐ exposed CSflies. Together, these findings suggest that hyperdopaminergic signaling augments the effect of social enrichment on the ethanol response. The findings of this study provide important information regarding the mechanism by which genetic (dopamine transporter) and non‐genetic (social context) factors interact for the locomotor response to ethanol.