不同剂量异丙酚在新生大鼠不同脑区的分布

Regional distribution of propofol at different doses in the brain during propofol anesthesia in neonatal rats

目的探讨新生大鼠异丙酚腹腔麻醉的理想剂量及异丙酚在新生大鼠不同脑区的分布。方法第一部分:将新生大鼠随机分为5组,分别腹腔注射不同剂量的异丙酚,分别记录麻醉状态、维持时间、动脉血气,比较得出新生大鼠腹腔麻醉的理想异丙酚剂量。第二部分:将新生大鼠随机分为麻醉组(A组)和镇静组(S组),根据第一部分实验结果,腹腔注射镇静与麻醉剂量的异丙酚,在合适麻醉深度时断头法处死大鼠,高效液相色谱法测定大鼠不同脑区异丙酚的浓度。结果 25 mg/kg异丙酚腹腔注射可使新生大鼠达到镇静状态,而75 mg/kg则可达到外科满意的麻醉状态,并不引起内环境的异常。S组内,丘脑的异丙酚浓度明显高于其他脑区(P<0.05),其余部位间无明显差异。A组额叶、顶叶皮质异丙酚浓度明显低于其他脑区,海马、扣带回的异丙酚浓度明显高于其他脑区(P<0.05),其他脑区无明显差异。结论腹腔注射异丙酚是适合新生大鼠的麻醉方法,且当异丙酚剂量不同时,其在不同脑区的分布存在差异。

Objective To investigate the proper dose of propofol injected intraperitoneally（ i. p.） in neonatal rats and to study the regional distribution of propofol at different doses in the neonatal brain. Methods Part I： Sixty postnatal7-day-old rats were randomly divided into 5 groups,which received different doses of propofol injected i. p. The behavior,anesthetic intervals and arterial blood gas were recorded. Part II： Twenty neonatal rats were randomly divided into 2groups： anesthesia group（ group A） and sedation group（ group S）,and were injected propofol i. p. at the proper dose according to the results of Part I. Rats were decapitated when they reached the ideal anesthesia depth. The regional concentration of propofol in different regions of the brain was examined by high performance liquid chromatography. Results 25 mg / kg propofol i. p. was the sedate dose for neonatal rats,while 75 mg / kg i. p. was the anesthetic dose. In the group S,the concentration of propofol in the thalamus was significantly higher than in other regions（ P〈0. 05）,while in the group A,the concentrations of propofol in the frontal and parietal cortex were obviously lower,and the concentrations of propofol in the hippocampus and cingulate gyrus were obviously higher than that in other regions（ P〈0. 05）. Conclusions Propofol is a suitable anesthetic for neonatal rats and its distribution in the brain is quite different when given at different doses.