外源性N-甲基-D-天冬氨酸对成年大鼠被动回避学习记忆的影响

目的 探讨脑内植入外源性N-甲基-D-天冬氨酸(NMDA)对成年大鼠被动回避学习记忆的影响. 方法 在大鼠脑内植入不同浓度的NMDA缓释膜片后,比较各组大鼠被动同避学习记忆(避暗实验)的能力以及额前腹内侧皮质(vMPFC)及扣带同前皮质(ACC)区域NMDA受体活性的区别. 结果 避暗实验中各组大鼠潜伏期和错误次数间差异无统计学意义(P=0.846,P=0.792).各组大鼠vMPFC及ACC区域的NMDA受体活性之间差异无统计学意义(P=0.546),但随着所植入的缓释膜片中NMDA浓度增加.这些区域NMDA受体活性有降低的趋势. 结论 外源性植入NMDA对成年大鼠被动回避学习记忆无明显影响,但本实验为进一步研究NMDA改变受损脑组织的神经可塑性奠定了一定的基础.

Effect of exogenous N-methyl-D-aspartate on passive avoidance learning and memory in adult rats

Objective To assess the effect of exogenous N-methyl-D-aspartate (NMDA) on passive avoidance learning and memory in adult rats. Methods Slow-release films containing different concentrations of NMDA were prepared and placed on the surface of the rat brain through frontoparietal craniectomy. Three weeks after the operation, the results of step-through test and NMDA receptor activity in the ventromedial prefrontal cortex (vmPFC) and the anterior cingulate cortex (ACC) were compared between the groups. Results No significant differences were found in the latency time (P=0.846) and error frequency (P=0.792) in the step-through test, or in NMDA receptor activity in the vmPFC and ACC (P=0.546) among the groups 3 weeks after the operation. The NMDA receptor activity in these regions, however, tended to decrease with the increment of NMDA concentration in the slow-release films. Conclusion Exogenous NMDA does not produce obvious effect on passive avoidance learning and memory in adult rats. The results of this experiment may provide the basis for further studies of the effects of NMDA in altering the neural plasticity in the impaired brain.