Jennifer Anne Jennings

"The Combined Effects of Nicotine and Ethanol Exposure During Embryogenesis in Zebrafish" (Jennings, Ndiaye, & Sudhesh, 2023)

Associated with GMU Neuroscience Interdisciplinary Program - Semester Research conducted under the supervision of Dr. Gwendolyn Lewis at the Krasnow Institute for Advanced Study at George Mason University, Fairfax, VA

Fall 2023 Scientific Poster 

This study assessed the combined effects of nicotine and ethanol exposure during embryogenesis in zebrafish as a model for placental exposure in pregnant women who smoke and drink. While the individual effects of nicotine and ethanol are understood, investigation into how the co-use of these drugs regarding molecular signaling and development is lacking. AB strain Zebrafish aged at 4-hours post fertilization (hpf) were divided and placed into one of the four treatment conditions: plain egg water, 10uM Nicotine, 1.5% ETOH, and 10uM Nicotine & 1.5% ETOH for up to 24 hours. They were analyzed at 24hr, 48hr, and 72hr for morphological characteristics and locomotor behavior. Co-exposure to ethanol (1.5%) and nicotine (10uM) produced heart rate variability (arhythmic heart beats), pericardial edemas, and severe phenotypic abnormalities. Co-treatment trended towards a decreased presence of touch-evoked tail coils at 24-hours post-treatment exposure while significantly decreasing the presence of a startle response at 48-hours. Based on the characteristics assessed, the results indicate that co-treatment did not enhance either drug's effect on embryonic development in zebrafish. Both qualitative and quantitative findings indicated that co-treated embryos resemble phenotypic and locomotor characteristics like that of embryos exposed only to ethanol (1.5%) at 24- and 48-hours post-drug exposure, but resembe locomotor behaviors like that of embryos exposed only to nicotine (10uM) at 72-hours post-drug exposure. Exposure either in isolation or under co-treatment with nicotine significantly affected cardiac development across all time points and produced arrhythmic heartbeats.