Early Life Adversity Disrupts Social Preference and Opioid Reward Mechanisms in Adolescent Mice

Abstract

<b>Abstract ID 22240</b> <b>Poster Board 1</b> Early life adversity in form of poor postnatal care is a major developmental stressor impacting behavior later in life. Previous studies have shown the impact of early life stress on behavioral and neural abnormalities. Specifically, research have demonstrated how early life stress in form of reduced bedding and nesting materials can result in sex-specific behavioral deficits and aberrations in the cerebellar regions of adult rodents. Little is known about how such alterations in cerebellar regions due to early developmental stress impact drug-seeking and reward mechanisms. To address this question, we assessed behavioral outcomes in adolescent C57/BL6 mice who were exposed to limited bedding and nesting materials at postnatal days 2–9. The animals were tested for a battery of behaviors including open field, novel object recognition, social preference, elevated plus maze, and morphine-induced conditioned place preference. There was a significant reduction in social preference in animals that underwent early-life stress compared to normally reared animals (t-test, p&lt;0.05). Our results also indicated that animals undergoing post-partum adversity had increased preference towards the morphine-paired chamber in the morphine-induced conditioned place preference test (t-test, p&lt;0.05). No differences were observed between the groups in novel object recognition or elevated plus maze. To identify cerebellar epigenetic markers that might underlie these behavioral deficits, we performed mRNA analysis of deep cerebellar nuclei and identified putative factors that might have a role in these behaviors. The current study aims to further understand how stress-induced neurodevelopmental changes can influence neuronal remodeling and affect addiction vulnerability in adolescents. This project was funded by grants R01DA044999 and P20GM103434 from the National Institutes of Health.