Orexin-A对氯胺酮麻醉老年大鼠苏醒的影响

Effect of orexin-A on recovery from ketamine anesthesia in aged rats

目的观察Orexin-A对老年大鼠氯胺酮麻醉后苏醒及认知功能的影响。方法将55只老年大鼠随机分为空白对照组10只,模型对照组、Orexin-A低剂量组、Orexin-A高剂量组各15只。以100mg/kg氯胺酮腹腔注射建立麻醉模型。麻醉10min后,治疗组侧脑室注入Orexin-A1、4nmol/10μl。对照组注入等量人工脑脊液。观察各组大鼠麻醉后翻正反射持续时间;侧脑室给药前后脑电图δ波相对比的变化;Morris水迷宫检测学习记忆功能。结果氯胺酮麻醉可使老年大鼠学习记忆能力明显下降,Orexin-A能明显缩短麻醉后大鼠翻正反射持续时间,减少δ波的相对比例,并能改善麻醉后老年大鼠的学习记忆能力,以较大剂量效果显著(P<0.05)。结论Orexin-A对氯胺酮麻醉后老年大鼠具有促醒作用,且能明显改善麻醉后大鼠认知功能。

Objective To observe the effect of orexin-A on the recovery and cognitive function of aged rats after ketamine anesthesia. Methods Fifty-five aged rats were divided randomly into control group, model control group, 1 nmol/L Orexin-A group, and 4 nmol/L Orexin-A group. In the latter 3 groups, the rats received an intraperitoneal injection of ketamine at 100 mg/kg, and normal saline was injected in the control group. Ten minutes after the injections, the rats received intraventricular injections of artificial cerebrospinal fluid （control and model control group） or of 10 μl 1 or 4 nmol/L Orexin-A as indicated. The behavioral changes of the rats were assessed by the duration of loss of righting reflex （LORR）. Electroencephalogram （EEG） recordings were used to evaluate the changes in rat brain activity by comparison of the percent of δ wave in EEG before and after the intraventricular injections. Morris water maze was used to test the learning and spatial localization abilities of the rats. Results Ketamine resulted in obvious impairment of learning and memory abilities of the aged rats. Orexin-A at 4 nmol/L induced significant decrease in the duration of LORR and marked reduction of δ activities in anesthetic rats （P〈0.05）, and obviously improved the learning and spatial localization abilities of the rats after anesthesia （P〈0.05）. Conclusion Orexin-A can promote the recovery and improve the cognitive fimction of aged rats after ketamine anesthesia .