title: Electroencephalographic and physiologic changes after tricaine methanesulfonate immersion of African clawed frogs (Xenopus laevis).
abstract: The objective of this study was to determine electroencephalographic and complementary physiologic changes in Xenopus leavis frogs after bath immersion in MS222. We also evaluated the addition of sodium pentobarbital injected intracoelomi- cally 2 h after MS222 immersion to achieve  euthanasia. Frogs (n = 9) weighing 105.5 ± 8.4 g (mean ± 1 SD) were immersed in MS222 at either 1 or 3 g/L until anesthesia was achieved; a conductive stainless steel screw then was implanted in the skull on top of the outer pial surface of the brain. Frogs were immersed  again in MS222 at the same concentration as previously, and electroencephalograms, heart rate, oxygen saturation, and respiratory movements were recorded. Amplitude and mean frequency of the electroencephalographic signal were evaluated at 15-min intervals until a flat-line signal was achieved.  At 2 h after induction, frogs were injected intracoelomically with sodium pentobarbital (0.5 mL; 240 mg/mL) to accelerate euthanasia. Immersion of frogs in 1 or 3 g/L of MS222 depressed cerebral activity within 30 min without a significant effect on cardiac function. Intracoelomic injection  of sodium pentobarbital at 2 h after MS222 administration rapidly (3.2 ± 1.7 min) induced cardiac arrest. In conclusion, immersion in MS222 can be used for the collection of organs from X. laevis frogs, but the addition of pentobarbital is required to achieve euthanasia.
authors: Department of Veterinary Biomedicine, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Canada.
authors: Vanessa
authors: V
authors: Lalonde-Robert
authors: Sébastien
authors: S
authors: Desgent
authors: Sandra
authors: S
authors: Duss
authors: Pascal
authors: P
authors: Vachon
mesh_terms: D062365:Aminobenzoates / Q000008:administration & dosage; D000758:Anesthesia / Q000379:methods / Q000662:veterinary; D000777:Anesthetics / Q000008:administration & dosage; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D004333:Drug Administration Routes; D004569:Electroencephalography / Q000662:veterinary; D037901:Euthanasia, Animal / Q000941:ethics / Q000379:methods*; D005260:Female; D006323:Heart Arrest / Q000139:chemically induced / Q000662:veterinary; D006339:Heart Rate / Q000187:drug effects; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007101:Immersion; D010100:Oxygen / Q000378:metabolism; D010424:Pentobarbital / Q000008:administration & dosage; D012119:Respiration / Q000187:drug effects; D013997:Time Factors; D014982:Xenopus laevis / Q000502:physiology*
chemical_list: D062365:Aminobenzoates; D000777:Anesthetics; D006993:Hypnotics and Sedatives; C003636:tricaine; D010424:Pentobarbital; D010100:Oxygen