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Updated: Jun 19, 2026
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Effective Rapid Blood Perfusion in Xenopus
Published on: May 16, 2023
Evaluation and refinement of euthanasia methods for Xenopus laevis
Stéphanie L Torreilles1, Diane E McClure, Sherril L Green
1Department of Comparative Medicine, Stanford University, Stanford, CA, USA. storreil@stanford.edu
Summary
Euthanizing Xenopus frogs requires higher doses of tricaine methane sulfonate (MS222) or alternative methods like sodium pentobarbital or benzocaine gel for reliable euthanasia. These findings provide crucial data for humane amphibian research practices.
Area of Science:
- Veterinary Medicine
- Amphibian Research
- Animal Welfare
Background:
- Tricaine methane sulfonate (MS222) is the standard euthanasia method for Xenopus.
- Previous MS222 dosage recommendations lack dose-response data and reliability assessments.
Purpose of the Study:
- Evaluate euthanasia efficacy of MS222 immersion and alternative methods in Xenopus.
- Determine reliable euthanasia protocols for Xenopus laevis.
Main Methods:
- Dose-response testing of MS222 immersion (1-5 g/L) for individual and grouped frogs.
- Assessment of intracoelomic MS222 injection, intracoelomic sodium pentobarbital with phenytoin injection, and ventral benzocaine gel application.
Main Results:
- Euthanasia requires at least 1 hour immersion in 5 g/L MS222, 1100 mg/kg sodium pentobarbital with phenytoin, or 182 mg/kg benzocaine.
- These effective doses are significantly higher than previously recommended levels for Xenopus.
Conclusions:
- Current Xenopus euthanasia protocols may be insufficient.
- Revised, higher dosages or alternative methods ensure humane and complete euthanasia.
