Determination of sensitivity of male Wistar rats to an equal dose of ketamine/xylazine injection at anesthetic dose in a chronic model of hypernatremia in comparison with control group.

OBJECTIVE To determine the sensitivity to an equal dose of ketamine/xylazine injection at anesthetic dose in a chronic model of hypernatremia. METHODS This study was conducted at the Department of Physiology, Zanjan University of Medical Science, Zanjan, Iran in 2004. Sixty male Wistar rats, weighing 250 +/- 20 g were randomly allocated to 3 groups. The control group was provided with tap water, and first and second test groups consumed 1% and 2% salt concentrations for 144 hours. One hundred mg/kg ketamine and 10 mg/kg xylazine were used as an anesthetic agent. The measured anesthetic parameters comprises of righting reflex latency, required time for establishment of animal's immobility, immobility period, required time for appearance of animal's mobility and complete re-establishment of the righting reflex. RESULTS The required time for inhibition of the righting reflex and animal's mobility in the second group was significantly shorter than the first and control groups. Immobility period, required time for appearance of animal's mobility and complete re-establishment of the righting reflex in the second group were significantly longer than the first and control groups. CONCLUSION Hypernatremia increases the speed of transition from different steps of ketamine/xylazine anesthesia with significant delay in immobility period and recovery from anesthesia in rats, hence, anesthetic dose reduction in hypernatremia is necessary.