High-Throughput Method for Measuring Alcohol Sedation Time of Individual <em>Drosophila melanogaster</em>

Abstract

Drosophila melanogaster provides an excellent model to study the genetic underpinnings of alcohol sensitivity. In contrast to studies in human populations, the Drosophila model allows strict control over genetic background, and virtually unlimited numbers of individuals of the same genotype can be reared rapidly under well-controlled environmental conditions without regulatory restrictions and at relatively low cost. Flies exposed to ethanol undergo physiological and behavioral changes that resemble human alcohol intoxication, including loss of postural control, sedation, and development of tolerance. Here, we describe a simple, low-cost, high-throughput assay for assessing alcohol sedation sensitivity in large numbers of single flies. The assay is based on video recording of single flies introduced without anesthesia in 24-well cell culture plates in a set-up that enables synchronous initiation of alcohol exposure. The system enables a single person to collect individual ethanol sedation data on as many as 2,000 flies within an 8 h work period. The assay can, in principle, be extended to assess the effects of exposure to any volatile substance and applied to measure effects of acute toxicity of volatiles on other insects, including other fly species. Video LinkThe video component of this article can be found at https://www.jove.com/video/61108/ 13,15,19,20 . Whereas inebriometer assays have led to identification of genes, genetic networks, and cellular pathways associated with alcohol sedation sensitivity and development of tolerance 12,13,14,21 , the assay is time consuming, low-throughput, and ineffective for measuring alcohol sensitivity in single flies.Alternative ethanol sedation assays that do not require the elaborate inebriometer set-up allow for more convenient measurements but are still limited in throughput and generally require analyses of groups of flies rather than individuals 21,22,23,24,25 . Assessing single flies minimizes the

Perspectives on the Drosophila melanogaster Model for Advances in Toxicological Science

“…Administration of volatile toxicants has technical challenges, yet has been executed in a number of studies with definitive findings for the effects and gene candidates mediating ethanol and benzene toxicity and other volatile organics (Guarnieri & Heberlein, 2003; Inamdar et al., 2014; Li et al., 2022; Morozova et al., 2015; Sass et al., 2020). This mode of delivery is feasible and easier to implement for airborne delivery of toxicants in Drosophila than it is for other model organisms (e.g., Caenorhabditis elegans and zebrafish).…”

“…A microtiter plate–based high‐throughput assay for alcohol sensitivity has been developed where alcohol knockdown time is measured when flies are exposed to ethanol vapors (Sass et al., 2020). This assay can, in principle, be applied to any toxic vapor.…”