• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.286-293
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• 2003

The cardiopulmonary and antagonistic effects of atipamezole, to medetomidine (30 ug/kg, IM)-tiletamine/zolazepam (10 mg/kg, IV) were determined. Twelve healthy mongrel dogs ,(4.00$\pm$0.53 kg, mean$\pm$SD) were randomly assigned to the four experimental groups (control, A30; atipamezole 30 ug/kg, A60; atipamezole 60 ug/kg, A150; atipamezole 150 ug/kg) with 3 dogs in each group. Atropine (0.03 mg/kg, IM), medetomidine, and tiletamine/zolazepam (TZ) were injected 10 minute intervals. Atipamezole was injected intravenously 15 minutes after TZ injection. Mean arousal time (MAT) was 52.50$\pm$4.98, 43.06$\pm$2.60, 32.83$\pm$8.13, and 14.36$\pm$1.60 minutes in control, A30, A60, and Al50 groups respectively. In Al50 group, MAT was significantly reduced (P < 0.05). but mean walking time (MWT) was similar to that in control group. In recovery period, the higher doses of atimapezole, the rougher recovery including head rocking, hypersalivation, and muscle twitching. Five of twelve dogs vomited within 5 minutes after medetomidine injection. In Control group, heart rate significantly decreased in all recording stages except 15 minutes after TZ injection, 10 minutes after medetomidine injection in all groups, and 40 minutes after atipamezole injection in A30 group (P < 0.05). In Al50 group, atipamezole reversed the respiratory depression induced by medetomidine. Arterial blood pressure was significantly decreased 10minutes after medetomidine injection and 15 minutes after TZ injection in almost dogs in this study (P < 0.05). From 10 minutes after atipamezole injection to arousal time, arterial blood pressure was progressively increased in A60 and A150 group. Any value of blood gas analysis and CBC, and serum chemistry values were not significantly changed except pH of Al50 at 10 minutes after medetomidine injection. As shown in present study, atipamezole(150 ug/kg) is considered to exert a useful reversal effect in dogs anesthetized with medetomidine-tiletamine/zolazepam combination.