Highlight Article: Conditioning the neuroimmune response to ethanolusing taste and environmental cues in adolescent and adult rats

摘要

Our work in adult Sprague-Dawley rats has shown elevation of the cytokineInterleukin (IL)-6 in the hippocampus and amygdala following acute and repeatedbinge-like doses of ethanol during intoxication. Previously, we have shown thatin adults, the central IL-6 response to a sub-threshold dose of ethanol wassensitized by repeated pairings of ethanol as an unconditioned stimulus (US)with an odor conditioned stimulus (CS).In the present studies, acute ethanolexposure (4 g/kg intraperitoneal) was paired with a combined odor and taste cueusing a single trial learning procedure, after which rats were tested forconditioned effects of the CS on neuroimmune gene expression. We found that IL-6was significantly elevated in the amygdala based on exposure to the CS afterjust one CS–US pairing in young adolescent rats (age P32–40), an effect that wasmore modest in young adults (P72–80). These data indicate that, despite a normaldisposition toward a blunted neuroimmune response to ethanol, adolescents weremore sensitive than adults to forming learned associations between ethanol’sneuroimmune effects and conditioned stimuli. Given the emergent role of theimmune system in alcoholism, such as regulating ethanol intake, theseethanol-induced conditioned effects on cytokine levels may contribute to ourunderstanding of the unique attributes that make adolescence a time period ofvulnerability in the development of later alcohol abuse behaviors.