Analyses of anaesthesia with ketamine combined with different sedatives in rats

The goal of this study was to establish an easy-to-perform, reliable, and safe protocol for intraperitoneal injection anaesthesia in rats, as well as an easy method to assess anaesthesia depth under routine clinical conditions. Seventy Wistar rats (35 males and 35 females) were used to evaluate intraperitoneal anaesthesia with ketamine (75 mg/kg) combined with one of the following central nervous system depressors: acepromazine (2.5 mg/kg), diazepam (5 mg/kg), medetomidine (0.5 mg/kg), midazolam (5 mg/kg) and xylazine (2.5 mg/kg). Significant differences were found between the combinations in ataxia, recovery and righting parameters, as well as respiratory and heart rates and haemoglobin saturation by oxygen, whereas significant differences between sexes for the parameters of ataxia, hypnosis, recovery, righting and exploratory behaviour were observed upon waking. The best results for parameters such as induction, and maintenance and recovery from anaesthesia (more regular and stable) were observed with alpha(2)-agonists: ketamine/xylazine in males and ketamine/medetomidine in females.