Résumé : We hypothesized that interference of opiate antagonist-precipitated withdrawal signs under anesthesia is anesthetic-specific. Three groups of morphine-dependent rats were compared in different experimental conditions using a protocol of rapid withdrawal induction by an antagonist under anesthesia. We observed that ketamine and midazolam have different effects on the expression of withdrawal. This brings specific insights into the pharmacological basis of therapy with induction of opiate antagonist.