Discipline: Biological Sciences
Subcategory: Cell and Molecular Biology
Curteisha Jacobs - Harris-Stowe State University
Co-Author(s): Sandra Leal, Harris-Stowe State University, St. Louis, MO
Monosodium glutamate (MSG) is a common salt additive used to enhance the flavor of food. We hypothesize that consuming food containing MSG on a frequent basis may develop into an addictive behavior. Thus, consuming MSG may increase dopamine (DA) levels in the reward center of the brain. Specifically, DA is a ‘feel good’ neurotransmitter released from the nucleus accumbens of the human brain. To determine whether MSG consumption affects DA levels in the brain, we used Drosophila larvae as a simple model system to validate the hypothesis. Larvae developing throughout the first-, second, and third-instar stages were fed either regular yeast- paste or yeast-paste containing increasing doses of sodium chloride (NaCl) or MSG. Late third-instar larva was then subjected to behavioral assays to measure the effects of MSG on rhythmic behaviors (body wall and mouth hook contractions) or non-rhythmic behaviors (mechanosensory and righting reflex). We uncovered differential effects on rhythmic, locomotor body wall contractions (BWCs). Specifically, we found that at a low dosage of MSG (1 mg/ml) decreased the number of BWC, while MSG at an intermediate (50mg/ml) dosage had no effect on BWCs. A high dose of MSG at a (100 mg/ml) dosage also dampened locomotor activity. Virgin male and female adult flies were subjected to a taste preference assay based on published procedures to determine whether they are attracted to MSG; these studies are currently ongoing. However, we have shown that flies are attracted to sucrose as a validation of the assay methods. At present, the results indicate that MSG may function as a neurotransmitter in larvae based on rhythmic assays while not having major effects on non-rhythmic behaviors. As indicated, adult preference assays are ongoing. Future studies are planned to measure DA transcript levels as well as transcript levels for markers of obesity from the brains of MSG-treated larvae and/or adults. While obesity is a health epidemic in America of paramount concern, food additives such as MSG with potential addictive properties must be considered as contributing factors to unhealthy eating habits leading to the development of obesity.
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Funder Acknowledgement(s): Funding was provided by an NSF grant to Harris- Stowe State University: HBCU- UP Implementation Grant Award, PI: Dr. Dwayne Smith MOLSAMP Award September, 2017 - Present, PI: Dr. Dwayne Smith
Faculty Advisor: Sandra Leal, email@example.com
Role: I am solely responsible for my research project including all behavioral studies.