Rocinholi L F, Almeida S S, De-Oliveira L M
Laboratório de Nutriçäo e Comportamento, Faculdade de Filosofia, Ciências e Letras de Ribeiräo Preto, Universidade de São Paulo, Brasil.
Braz J Med Biol Res. 1997 Mar;30(3):407-13. doi: 10.1590/s0100-879x1997000300016.
Two animal models of pain were used to study the effects of short-term protein malnutrition and environmental stimulation on the response threshold to aversive stimuli. Eighty male Wistar rats were used. Half of the pups were submitted to malnutrition by feeding their mothers a 6% protein diet from 0 to 21 days of age while the mothers of the other half (controls) were well nourished, receiving 16% protein. From 22 to 70 days all rats were fed commercial lab chow. Half of the animals in the malnourished and control groups were maintained under stimulating conditions, including a 3-min daily handling from 0 to 70 days and an enriched living cage after weaning. The other half was reared in a standard living cage. At 70 days, independent groups of rats were exposed to the shock threshold or to the tail-flick test. The results showed lower body and brain weights in malnourished rats when compared with controls at weaning and testing. In the shock threshold test the malnourished animals were more sensitive to electric shock and environmental stimulation increased the shock threshold. No differences due to diet or environmental stimulation were found in the tail-flick procedure. These results demonstrate that protein malnutrition imposed only during the lactation period is efficient in inducing hyperreactivity to electric shock and that environmental stimulation attenuates the differences in shock threshold produced by protein malnutrition.
使用两种疼痛动物模型来研究短期蛋白质营养不良和环境刺激对厌恶性刺激反应阈值的影响。使用了80只雄性Wistar大鼠。一半幼崽在0至21日龄时通过给其母亲喂食6%蛋白质饮食而遭受营养不良，而另一半（对照组）的母亲营养良好，接受16%蛋白质。从22至70日龄，所有大鼠均喂食商业实验室饲料。营养不良组和对照组中的一半动物饲养在刺激条件下，包括从0至70天每天进行3分钟的处理以及断奶后饲养在丰富的生活笼中。另一半饲养在标准生活笼中。在70日龄时，将独立的大鼠组暴露于电击阈值或甩尾试验中。结果显示，与断奶和测试时的对照组相比，营养不良大鼠的体重和脑重较低。在电击阈值试验中，营养不良的动物对电击更敏感，环境刺激提高了电击阈值。在甩尾试验中未发现饮食或环境刺激造成的差异。这些结果表明，仅在哺乳期施加的蛋白质营养不良可有效诱导对电击的反应过度，并且环境刺激可减轻蛋白质营养不良产生的电击阈值差异。
