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Methods and Datasets for 5-Day Oral Anatoxin-a Toxicity in Mice
Citation:
Jenkins-Hill, D., D. Herr, G. Jung, Kathy McDaniel, D. Macmillan, L. Strader, C. Wood, J. Cullen, B. Ruto, AND T. Jackson. Methods and Datasets for 5-Day Oral Anatoxin-a Toxicity in Mice. U.S. Environmental Protection Agency, Washington, DC, 2026. https://doi.org/10.23719/d-kzbz
Impact/Purpose:
This subproduct contains the methods and datasets for the oral anatoxin 5-day study.
Description:
Anatoxin-a (ATX) is a neurotoxic cyanotoxin found in freshwater globally. Multiple genera of cyanobacteria can produce anatoxins and include producers associated with planktonic blooms such as Aphanizomenon, Dolichospermum, and Planktothrix and those most associated with benthic blooms, Microcoleus and Phormidium . Exposure is most often by the oral route and can be related to accidental ingestion during recreational activities, exposure in drinking water, contamination of food supplements, or when ATX has accumulated in fish tissue. ATX is a potent agonist at nicotinic acetylcholine receptors (nAChR) with a higher affinity for the receptor than the biological neurotransmitter, acetylcholine, and the receptor agonist, nicotine. ATX binds to the nAChR and is not affected by acetylcholinesterase, the enzyme which splits and recycles acetylcholine. This action at the neuromuscular receptors causes muscle contraction which exhausts the energy of the muscle and results in flaccid paralysis. The signs of ATX intoxication include generalized muscle weakness, ataxia, tremors, and respiratory suppression which can lead to death by asphyxiation with higher exposures. The rapid onset of effects is responsible for ATX originally being known as the “very fast death factor” (VFDF) and has caused illness and death in pets, livestock, and wildlife. Existing data is limited for establishing health guidelines for anatoxin. The anatoxin-a 5-day study in CD-1 mice was designed in response to a request from Regions 8 and 10 and the Office of Water to have health effects data for repeat dose exposure of anatoxin. The study was designed with a vehicle control and 2, 4, and 6 mg/kg dose groups with males and females (n=10/dose/sex). A single oral dose was given by gavage for 5 consecutive days. A behavioral functional observational battery was performed pre- and post-dosing. Following the post-dosing test, a second behavioral test for memory, learning and cognition was done, the novel objects recognition. The mice were necropsied for body weight, gross exam, and collection of blood for serum, liver, and brainstem. The serum was used for serum chemistry and metabolomics while the liver and brainstem were used for transcriptomic analysis. The testes and epididymides were collected, weighed, and assessed for sperm motility, sperm count, and testicular histology. A subset of 6 mg/kg male mice were also used for auditory testing to evaluate anatoxin as a potential ototoxic agent. This subproduct will make the datasets produced in this study available to the public.
