Fukuda M T H, Françolin-Silva A L, Hernandes A S, Valadares C T, Almeida S S
Laboratory of Nutrition and Behavior, FFCLRP, University of São Paulo, Avenida dos Bandeirantes, 3900, Ribeirão Preto, SP 14040-901, Brazil.
Nutr Neurosci. 2007 Oct-Dec;10(5-6):251-9. doi: 10.1080/10284150701723818.
The present study investigated the effects of early protein malnutrition on the spatial learning and memory processes. The consequences of malnutrition for the cholinergic system were evaluated by comparing the performance of malnourished and control animals in the Morris water maze after treatment with scopolamine. The learning test consisted of placing the animal in the maze to escape to a submerged platform with 12 trials per day for two consecutive days. After 24 trials, the platform was removed, the rats were placed in the maze and the time spent by them in each quadrant was recorded. After 28 days the animals were tested in a single trial to verify the retention of the spatial information. In the first Experiment, scopolamine (0.0, 0.2, 0.4 and 0.6 mg/kg per ml. i.p.) was administered 20 min before the experimental sessions. In the second experiment, a dose of 0.6 mg/kg was administered after the sessions, during the period in which learning consolidation occurs. In the first experiment, there was a significant effect of the drug, with scopolamine impairing, learning in both nutritional conditions. In the saline condition, control animals presented a better performance when compared with malnourished animals. However, 28 days later, both groups increased their latencies. With 0.2 and 0.4 mg/kg of scopolamine, the performance of both nutritional groups was similar and with 0.6 mg/kg malnourished animals performed better than controls. In the second experiment, malnourished animals were also less reactive to the effects of scopolamine, resulting in lower impairments as compared to control animals. These data suggest long-term changes in learning and memory as the result of changes produced by protein malnutrition in the cholinergic neurotransmitter system.
本研究调查了早期蛋白质营养不良对空间学习和记忆过程的影响。通过比较营养不良动物和对照动物在东莨菪碱处理后在莫里斯水迷宫中的表现，评估了营养不良对胆碱能系统的影响。学习测试包括将动物放置在迷宫中，使其逃向一个水下平台，每天进行12次试验，连续进行两天。经过24次试验后，移走平台，将大鼠放入迷宫中，并记录它们在每个象限所花费的时间。28天后，对动物进行单次试验，以验证空间信息的保留情况。在第一个实验中，在实验环节前20分钟腹腔注射东莨菪碱（0.0、0.2、0.4和0.6毫克/千克每毫升）。在第二个实验中，在实验环节后，即在学习巩固期，注射0.6毫克/千克的剂量。在第一个实验中，药物有显著作用，东莨菪碱在两种营养条件下均损害学习。在生理盐水条件下，对照动物与营养不良动物相比表现更好。然而，28天后，两组的潜伏期均增加。使用0.2和0.4毫克/千克的东莨菪碱时，两个营养组的表现相似，而使用0.6毫克/千克时，营养不良动物的表现优于对照动物。在第二个实验中，营养不良动物对东莨菪碱的作用也反应较小，与对照动物相比损伤较小。这些数据表明，蛋白质营养不良导致胆碱能神经递质系统发生变化，从而引起学习和记忆的长期改变。
