Yohimbine reduces neuropathology induced by ketamine/xylazine anesthesia

Ketamine, an NMDA receptor antagonist, is commonly used in combination with xylazine, an alpha 2-adrenergic receptor agonist, to induce surgical anesthesia in birds and other vertebrates. Problems associated with this anesthetic combination include impaired thermoregulation, compounded by the inability to feed while anesthesia lasts (approximately 6 h after a single dose), and the ketamine-induced vacuolization of large cortical neurons. In the zebra finch, yohimbine (an alpha 2-adrenergic receptor agonist) counters the effects of ketamine/xylazine anesthesia, speeding recovery after the surgical procedure has been completed. In addition, administration of yohimbine reduces the formation of vacuoles in large cortical neurons and in neuropil. Yohimbine administration should be considered following all procedures involving ketamine/xylazine anesthesia.