The antagonistic effects of atipamezole and yohimbine on stress-related neurohormonal and metabolic responses induced by medetomidine in dogs

T. D. Ambrisko, Y. Hikasa

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This study aimed to compare the antagonistic effects of atipamezole (40, 120, and 320 μg/kg, IM), yohimbine (110 μg/kg, IM), and saline on neurohormonal and metabolic responses induced by medetomidine (20 μg/kg, IM). Five beagle dogs were used in each of the 5 experimental groups in randomized order. Blood samples were taken for 6 h. Medetomidine significantly decreased norepinephrine, epinephrine, insulin, and nonesterified fatty acid levels, and increased plasma glucose levels. Both atipamezole and yohimbine antagonized these effects. The reversal effect of atipamezole was dose-dependency, except on epinephrine. Yohimbine caused prolonged increases in plasma norepinephrine and insulin levels compared to atipamezole, possibly because of its longer half-life elimination. Only yohimbine increased the cortisol levels. Neither glucagon nor lactate levels changed significantly. Based on these findings, when medetomidine-induced sedation is antagonized in dogs, we recommend using atipamezole IM, from 2- to 6-fold the dose of medetomidine, unless otherwise indicated.

Original languageEnglish (US)
Pages (from-to)64-67
Number of pages4
JournalCanadian Journal of Veterinary Research
Issue number1
StatePublished - Jan 1 2003
Externally publishedYes


ASJC Scopus subject areas

  • veterinary(all)

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