Adolescent alcohol exposure disrupts episodic-like memory by impairing dopamine synapses in the mouse prelimbic cortex

Abstract

Heavy alcohol use during adolescence has a significant impact on cognitive functions, such as episodic memory, even after detoxification. However, in animal models, defects in episodic memory by adolescent alcohol exposure have not been consistently replicated, and thus, the brain regions and systems that are involved remain to be elucidated. Here, we show that adolescent alcohol exposure impairs episodic memory through the impairment of the dopamine system in the prelimbic region (PrL) of the medial prefrontal cortex in both females and males. Using mice as a model, we first show that adolescent alcohol exposure disrupts episodic-like memory in female and male adult mice. We then show that adolescent alcohol exposure decreases dopaminergic presynaptic terminals in the PrL in female and male mice. This decrease persists into adulthood. Finally, we show that the adult application of a D1 dopamine receptor agonist into the PrL of adolescent alcohol-exposed mice rescues episodic-like memory in female and male mice. Together, our results identify that dopaminergic synapses in the PrL play critical roles in the effects of adolescent alcohol use on episodic memory and provide a potential strategy to reverse memory deficits caused by adolescent alcohol use in both sexes.