| General anesthetics have varying influence on cardiac electrical activities such as heart rate in animals.These effects tend to interfere with the desired effect in anesthetized animals.Therefore,it is a very critical question in basic medical research field to choose appropriate general anesthetics according to different experimental animal in order to maximize reduce impact on animal ECG.But at present,there is a lack of comprehensive and systematic research on this problem.In the present study,six most commonly used anesthetics in basic medical experiments were used and the effective anesthetic dose and duration were observed in SD rats.The dynamic telemetry technique of the cardiac electrical implanter was used to measure the changes in heart rate and cardiac electrical activity before and after the animals were anesthetized,and to compare the effects of these anesthetics on electrical activity of animals.This work will provide experimental data on general anesthetics selection for different animals.The heart rate in rat is faster than human and the ECG waveform is different from human.During waking state,the EMG interference caused by limb activity can be influenced by the stability of ECG.Therefore,the observation and recording methods,related influencing factors and possible applications of the rat's ECG activity have been paid attention to in the field of biomedical research.In the present study,we used dynamic telemetry technique of the cardiac electrical implanter to determine effects of six anesthetics on electrical activity of rats.Objective: To observe the effects of different anesthetics on cardiac electrical activity by using the dynamic telemetry technique of the cardiac electrical implanter in rats.Method:Forty-eight SD rats were randomly divided into six groups,including: Isoflurane group,Propfol injection group,Etomidat group,Midazolam group,Pentobarbital group and Urethane group.Isoflurane group was used by inhalation,other groups were used by intraperitoneal injection.By surgical methods,implanters were embedded abdominally and subcutaneously.After the second day,cardiac electrical activity and heart rate were measured by DSI remote in conscious situation.Then each anesthetics were given at high or low dose respectively.Anesthesia induction period,maintenance period,recovery period of heart rate and ECG were recorded at 5min,10 min,15 min,20 min,30 min,60 min,90 min,120 min after administration in rats.Result:1 Anesthesia effect of six anesthetics on rats.Onset time of isoflurane group and propofol group is fast,and the anesthesia effects maintained stable and the rats can recover rapidly.Those drugs have the property of strong controllability.Onset time in etomidate group and in ketamine group is relatively fast,but the anesthesia effects maintained for a short time.Onset time in sodium pentobarbital group and urethane groups is slow,but anesthesia lasted for a long time,and the recovery is slow.2 Effects of six anesthetics on heart rate in normal ratsThe heart rate changes in isoflurane group and in propofol group were in a small range in 10-30 minutes of anesthesia observation.No obvious speed up or slow down were observed,and the heart rate is close to that in awake state.The trends of heart rate is gradually declined,with a most obvious effect at 30 minutes in etomidate group,sodium pentobarbital group and urethane group with prolongation of the duration of anesthesia.Ketamine group could be slightly accelerated heart rate and the heart rate variability is enhanced.3 Effects of six kinds of anesthetic on the accelerated heart rate in rats with isoproterenol.In conscious rats,the use of isoproterenol reached the peak effect in heart rate in 5 minutes after the drug applicaton.In 15 minutes or so,the heart rate basically returned to normal levels.In the presence of 6 kinds of different anesthetics,and then give isoproterenol,2% isoflurane and ketamine have the less affect on isoproterenol induced heart rate to the drug at 5 minutes after drugs application(P>0.05).The other four anesthetics can significantly reduce the effects of isoproterenol on heart rate.Conclusion:Soflurane and propofol have the best anesthetic effects in SD rats,and have little effect on heart rate.Amonge those,isoflurane have the minimum affect on isoproterenol enhanced heart rate,suggesting isoflurane is more suitable for the operation of anesthesia and for the study of the effect of some cardiovascular drugs on the heart rate. |
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