title: A benzodiazepine receptor antagonist improves emergence of mice from halothane anaesthesia.
abstract: The benzodiazepine receptor antagonist, flumazenil, at a dose of 10 mg/kg given intraperitoneally to mice, had no effect on the minimum air concentration (MAC-50) of halothane causing anesthesia in 50% of the animals and which was 1.0% by volume of the inhaled air. Diazepam, 10 mg/kg, potentiated the effect of halothane. When the mice had been pretreated with diazepam and flumazenil, 10 mg/kg or 20 mg/kg, partial but not complete reversal of the potentiating effect of diazepam was observed, minimum air concentration values being 0.6% after diazepam alone and 0.8% after diazepam and flumazenil. However, mice pretreated intraperitoneally with flumazenil, in the concentration range 1-10 mg/kg, delivered as a solution in polyethylene glycol-Intralipid vehicle or as a suspension in saline, recovered control levels of spontaneous motor activity much faster than in the absence of flumazenil, on emergence from halothane-induced anaesthesia. In this range, the effect was not dose-dependent. These findings suggest that some of the effects of halothane are mediated at the level of the benzodiazepine receptor.
authors.affiliation: Department of Anesthesiology and Intensive Care, Tel Aviv Medical Center, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Geller
authors.forename: B
authors.initials: B
authors.lastname: Schiff
authors.forename: P
authors.initials: P
authors.lastname: Halpern
authors.forename: Z
authors.initials: Z
authors.lastname: Speiser
authors.forename: S
authors.initials: S
authors.lastname: Cohen
mesh_terms: D000758:Anesthesia; D000818:Animals; D005442:Flumazenil / Q000494:pharmacology*; D006221:Halothane; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009043:Motor Activity / Q000187:drug effects; D004856:Postural Balance / Q000187:drug effects; D011963:Receptors, GABA-A / Q000187:drug effects*
chemical_list: D011963:Receptors, GABA-A; D005442:Flumazenil; D006221:Halothane