中文摘要：

目的探讨血管性痴呆（VD）大鼠海马神经型胆碱能受体（nAChR）的变化。方法改良四血管法建立VD大鼠模型；术后1个月，采用Morris水迷宫试验检测VD大鼠的学习和记忆功能；应用改良Ellman法测定大鼠血浆及海马乙酰胆碱酯酶（AChE）活性；Western Blot法及RT—PCR法分别检测大鼠海马nAChR亚单位α3、α4、α7蛋白及mRNA的表达水平，并与假手术组比较。结果与假手术组相比，VD组水迷宫试验逃避潜伏期明显延长，第1次穿越平台时间延长，穿越平台次数减少（均P〈0．01）；血浆AChE活性降低（P〈0．01），海马AChE活性升高（P〈0．05）；海马nAChR α3、α4、α7蛋白及nAChR α3、α7 mRNA表达水平明显下降（P〈0．05～0．01），nAChR α4 mRNA表达水平明显升高（P〈0．01）。结论海马神经元nAChR表达的降低可能是VD大鼠认知功能受损害的基础。

英文摘要：

Objective To explore the change of hippocampal neurons cholinergic receptor in rats with vascular dementia（VD）. Methods VD rat models were established by employing improved method of Pulsinelli＇ s fourvessel occlusion. 1 month later, the abilities of learning and memory of VD models were tested by Morris water maze. The activities of acetylcholinesterase （ AChE ） in plasma and hippocampus were detected by the improved Ellman＇s colorimetric methods. The expressions of hippocampal nicotinic acetyleholine receptor （nAChR） subunits α3, α4 and α7 proteins and mRNA were detected respectinely by Western Blotting and RT-PCR, respectively. The results were compared with sham operation group. Results Compared to the sham operation group, the escape latency of Morris water maze test and the first time crossing platform in VD group were significantly prolonged, the number of crossing platform was decreased （all P 〈 0. 01 ）. The activity in plasma AChE was significantly lower; while, in hippocampus was significantly higher（ all P 〈0. 05 ）. The expression of hippocampal nAChR subunits α3, α4 and α7 proteins and α3, α7 mRNA were obviously reduced （ P 〈 0. 05 - 0.01 ） ; while, the expression of nAChR α4 mRNA was increased （ P 〈 0. 01 ）. Conclusion Lower expression of hippocampal neurons nAChR may be the basis of impairment of the cognition function in VD rats.