建立脑内灌流叠氮钠所致的大鼠纹状体细胞外液乙酰胆碱水平下降的模型

The model on decreasing striatal extracellular acetylcholine level by intracerebral perfusion with sodium azide in rats

目的 建立可用于筛选防治老年退行性病变和其他脑细胞损伤所致智能减退药物的模型。方法应用脑内微透析技术 ,在清醒自由活动大鼠纹状体内灌流含叠氮钠 (NaN3,30mmol·L- 1)和新斯的明(10 μmol·L- 1)的林格液 ,连续收集透析液。用高效液相色谱 柱后固定化酶反应器 电化学检测器检测乙酰胆碱 (ACh)和胆碱水平。结果 脑内灌流NaN390min后该脑区细胞外液ACh水平较正常组持续下降 (P <0 .0 5～ 0 .0 1)。最低值在停止NaN3灌流后6 0min时出现 ,为相同时间点对照组水平的 10 .0 % ;此后有所恢复 ,但在恢复期 180min内未能达到对照组水平。阳性药甲磺酸阿米三嗪 (10mg·kg- 1·d- 1,ig ,灌流前连续给药 14d)可在停止NaN3灌流后 30和 6 0min时明显减缓ACh水平的下降 (均P <0 .0 5 )。结论 大鼠脑内灌流NaN3使局部脑区胆碱能神经功能损伤 ,可造成ACh水平持续下降的急性模型。

AIM To establish a usable method to screen the medicines for preventing and treating neurodegenerative diseases and intellective deficiency. METHODS Male Sprague Dawley rats were divided into 3 groups randomly: normal group, model group and Duxil group which was treated with Duxil 10 mg·kg -1 ·d -1 ig for 14 d. Utilizing the microdialysis technique to perfuse Ringer solution containing 10 μmol·L -1 neostigmine and NaN 3 30 mmol·L -1 into striatum of freely moving awake rats, and continuously collect the microdialysate sample simultaneously. The acetylcholine(ACh) and choline levels in microdialysate were measured with high performance liquid chromatography post column immobilized enzyme reactor electrochemical detection. RESULTS The extracellular ACh level was lower in model group than in control group after striatal perfusion with NaN 3 for 90 min. The decrease reached a minimum of 10.0%, at 60 min after stopping perfusion with NaN 3. Then the ACh level partially recovered. However, it did not reach the control level during 180 min of recovery. Pretreatment with Duxil alleviated the decrease in ACh induced by NaN 3 at 30 and 60 min after stopping perfusion with NaN 3. CONCLUSION Perfusion with NaN 3 caused the deficiency of cholinergic nerve activity in local brain, and it could be used as an acute model of sustained decrease in ACh level.