Comparison of anesthetic protocols indicates Japanese grass lizards (Takydromus tachydromoides) are insensitive to medetomidine

The systematic effects of anesthetics on reptiles remain obscure, and the present study evaluated the effects of intraperitoneal injections of 1) alfaxalone alone, 2) a combination of alfaxalone and midazolam, 3) a combination of medetomidine chloride, midazolam and butorphanol tartrate, 4) medetomidine chloride alone and 5) midazolam alone in Japanese grass lizards. The present findings indicated that a combination of alfaxalone (15 mg/kg) and midazolam (1 mg/kg) anesthetizes Japanese grass lizards for 1.5–3 h, whereas these lizards are apparently medetomidine-insensitive unlike some other reptiles. The effects of anesthetic and sedative agents differ among reptile species, and thus further studies should investigate the effects of anesthetics among reptiles.