PhD Exit Seminar for Amanda Facciol (Gerlai Lab)

Developmental Stage-Dependent Effects of Embryonic Ethanol Exposure on Social Behaviour and Potential Underlying Mechanisms in Adult Zebrafish: A Model for FASD

Abstract

Fetal Alcohol Spectrum Disorder (FASD) is characterized by a variety of morphological, behavioural, and cognitive deficits, including life-long learning disabilities and social dysfunction. FASD is a highly variable disorder, and symptoms range from mild to severe despite similar drinking patterns in mothers. One of the hypotheses proposed to explain this variability is the timing of alcohol consumption, or in other words, the developmental stage at which the embryo is exposed to alcohol. Due to their highly social nature, the zebrafish is becoming a popular model organism for investigating social deficits that arise from embryonic ethanol exposure. Previous studies in zebrafish have observed ethanol administered at 24 hours post fertilization (hpf) resulted in abnormal social behaviour accompanied by lower levels of dopamine and serotonin in the brain, however, little is known about how ethanol alters social behaviour and neurochemical systems at other developmental timepoints, and the mechanisms underlying these alterations remain unknown. Therefore, the goal of this thesis was two-fold: firstly, to investigate how the developmental stage of embryonic ethanol exposure differentially alters social behaviour and underlying neurochemistry, and second, to investigate novel mechanisms underlying embryonic ethanol-induced social deficits in adult zebrafish. Results presented here show both social behaviour and underlying neurochemistry are indeed impaired by ethanol in a developmental stage-dependent manner, however, the expression of ethanol-induced neurochemical dysfunction differed slightly depending on the age of observation. In adult zebrafish, abnormal social behaviour was accompanied by lower levels of whole brain dopamine, specifically when ethanol was administered at 10hpf, 16hpf and 24hpf, however, ethanol administered earlier (5hpf) and later (36hpf) had little to no effect. Additionally, abnormal social behaviour resulting from ethanol exposure at 24hpf was accompanied by lower levels of whole brain isotocin in adult zebrafish. Lastly, exposure to ethanol at 24hpf resulted in altered histone variant and neurochemical gene expression in adult zebrafish. These findings not only point to sensitive periods during early development but highlight potential new molecular candidates which may play an important role in the expression of embryonic ethanol-induced social deficits.

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Join Zoom Meeting

Wednesday, December 15^th, 2021 @ 10:10 AM

https://utoronto.zoom.us/j/89161866677

Meeting ID: 891 6186 6677

Host: Robert Gerlai (robert.gerlai@utoronto.ca)

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