Tiletamine/zolazepam and dexmedetomidine with tramadol provide effective general anesthesia in rats

Background:Tiletamine/zolazepam is a dissociative anesthetic combination commonly used in small animals but information is limited in rats.The alpha-2 agonist,dexmedetomidine,has gained popularity in laboratory animal anesthesia.Tramadol is a weak opioid mu agonist.The aim of this study was to assess whether the tiletamine/zolazepam/dexmedetomidine(ZD)combination effectively provides a surgical anesthesia plane comparable to tiletamine/zolazepam/dexmedetomidine with tramadol(ZDT)in a minor procedure in rats.Methods:Rats were induced with ZD or ZDT.After the loss of paw withdrawal,a small incision was made on the rats’left thighs as a surgical stimulus.Rats were maintained under a surgical anesthesia plane by assessing the loss of the paw withdrawal reflex for 45 minutes,then atipamezole was administered.Monitored anesthesia parameters included:(a)physiological parameters-pulse rate(PR),respiratory rate(RR),tissue oxygen saturation(%SpO 2),and body temperature;(b)duration parameters-induction time,onset and duration of surgical anesthesia plane,onset of recovery,and recovery time.Results:PR was significantly lower at 10 minutes in ZD and 5 minutes in ZDT groups.No difference was observed for RR,%SpO 2,and body temperature.Likewise,there were no differences for duration parameters:induction time was less than 3 minutes;onset and duration of surgical anesthesia plane were approximately 5 and 45 minutes,respectively;onset of recovery(time to move)was 51 minutes;and recovery time was 52 minutes,respectively.Conclusion:These data suggest the ZD combination provides a surgical anesthesia plane comparable to ZDT in a rat incisional pain model.