Naloxone Has No Effect on Nitrous Oxide Anesthesia


    loading  Checking for direct PDF access through Ovid

Abstract

It has been reported that naloxone antagonizes general anesthesia in rats when the tail clamp is used as a painful stimulus to assess anesthesia.1 The authors' hypothesis is that this antagonism is to the analgesic component of anesthesia only, and that anesthesia assessed by a non-painful stimulus would not be antagonized by naloxone. Therefore, the anesthetic potency of nitrous oxide in mice was measured using loss of the righting reflex as a non-painful stimulus. Naloxone, 2 and 16 mg/kg, intrapcritoncally, failed to antagonize nitrous oxide anesthesia measured 14–39 min after injection. Thus, 19 min after injection of naloxone, 2 mg/kg, the nitrous oxide ED50 was 1.25 ± 0.060 atm (n = 35), compared with 1.19 ± 0.053 atm (n = 35) after injection of saline solution (control). Following naloxone, 16 mg/kg, the nitrous oxide ED50 was 1.18 ± 0.059 atm (n = 35), compared with 1.22 ± 0.059 atm (n = 35) for saline solution. At neither dose of naloxone was the ED50 different from the control ED50, a finding that supports the authors' hypothesis.

    loading  Loading Related Articles