The objective of this study was to determine the level of
anesthesia attained in Xenopus laevis frogs using a
propofol bath administration. Thirty-three nonbreeding female Xenopus laevis frogs were used. At 175 mg/l, all frogs died after bath administration. An appropriate
anesthetic dose was determined to be 88 mg/l for 15 min. After administration of this dose, the
acetic acid test, withdrawal reflex, righting reflex, heart rate, and respiratory frequency were used to evaluate central nervous system depression. Pharmacokinetics of
propofol were calculated after blood concentration determination by tandem liquid chromatography-mass spectrometry analyses. Short-duration
anesthesia (less than 30 min) was obtained, and in many frogs,
muscular fasciculation was seen during the
acetic acid test. The area under the time-concentration curve (AUC0-t) was 24.07 microg.min/ml, and AUCinf was 24.71 microg.min/ml. The elimination half-life was 1.18 h. When administered as a single-bath immersion for 15 min,
propofol does not appear to be a safe and effective
anesthetic for Xenopus laevis frogs, due to a narrow dose-effect window, short duration, and shallow level of
anesthesia obtained.