Postoperative analgesics in South African Clawed frogs (Xenopus laevis) after surgical harvest of oocytes.

Heightened awareness for the welfare of earlier-evolved laboratory species has prompted increasing inquiries by institutional animal care committees, investigators, and laboratory animal veterinarians regarding the need for post-surgical analgesics in laboratory Xenopus. Basic research into the mechanisms and regulation of pain in Rana pipiens has demonstrated the clinical potential of opioid, alpha2-adrenergic, and non-opioid analgesic agents in amphibians. However, clinical studies using objectively established indices of amphibian pain, or pharmacological studies in either Rana pipiens or laboratory Xenopus have not been conducted. As discussed above, comparison of limited lethality data suggests that the safety index for these agents is quite narrow in Rana pipiens. Analgesic use in laboratory Xenopus has the added risk of drowning due to over sedation. Drug doses extrapolated from such studies and intended to provide pain relief in Xenopus should therefore be considered very carefully. An additional concern for laboratory Xenopus is that the effects of these agents on amphibian oogenesis, oocyte quality, and embryogenesis are unknown. As the numbers of laboratory Xenopus used in basic and biomedical research continues to increase, clinical studies that address all of these issues cannot come too soon.