title: Sedative effect of medetomidine and its reversal by atipamezole in house musk shrews (Suncus murinus).
abstract: This study was undertaken to evaluate the sedative effect of medetomidine, an alpha 2-adrenoceptor agonist, and the counteractive effect of atipamezole, an antagonist to medetomidine, in house musk shrews (Suncus murinus). Two hundred, 300, 400, or 600 micrograms/kg of medetomidine was intraperitoneal injected into 89 house musk shrews. A sedative effect was produced in one to two minutes after injection. The dose-dependent prolongation of the sedative duration and the dose-dependent appearance of a hypothermic effect were demonstrated. With 200 micrograms/kg of medetomidine, the sedative effect obtained was not adequate in some of the animals. With 300 micrograms/kg and above, a stable sedative state was induced in all the animals. The duration of sedation in the house musk shrews was much longer (p < 0.01) in males than in females. This suggested the higher susceptibility of male house musk shrews to this drug. The sedative effect and hypothermia obtained with 400 micrograms/kg of medetomidine were completely counteracted by more than 2.0 mg/kg of atipamezole. With 0.5 and 1.0 mg/kg of atipamezole, only a partial antagonistic action was produced. Transient vomiting appeared in 4.5% of the house musk shrews at approximately one minute after injection of medetomidine. This side-effect had occurred before the sedative effect was obtained, and was not serious enough to be a problem. None of the 89 house musk shrews died in this experiment. The above results show that the combination of medetomidine and atipamezole is a highly effective and safe anesthetic treatment which permits easy handling of house musk shrews.
authors.affiliation: Division of Veterinary Surgery, Nippon Veterinary and Animal Science University, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tagawa
authors.forename: Y
authors.initials: Y
authors.lastname: Hara
authors.forename: H
authors.initials: H
authors.lastname: Ejima
authors.forename: S
authors.initials: S
authors.lastname: Komori
authors.forename: T R
authors.initials: TR
authors.lastname: Saito
authors.forename: K W
authors.initials: KW
authors.lastname: Takahashi
authors.forename: K
authors.initials: K
authors.lastname: Hioki
authors.forename: S
authors.initials: S
authors.lastname: Ebukuro
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D007093:Imidazoles / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D020926:Medetomidine; D012788:Shrews / Q000502:physiology*
chemical_list: D000317:Adrenergic alpha-Antagonists; D006993:Hypnotics and Sedatives; D007093:Imidazoles; C050701:atipamezole; D020926:Medetomidine