Learning and memory of rats after long-term administration of low doses of parathion
Learning and memory of rats after long-term administration of low doses of parathion
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DOI：
10.1093/toxsci/46.1.101
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发表时间：
1998-11-01
影响因子：
3.8
通讯作者：
Machemer, L
中科院分区：
文献类型：
--
作者：
Ivens, IA;Schmuck, G;Machemer, L
采用一套四项学习记忆测试（Morris Maze I用于参考记忆，Morris Maze II用于工作记忆，单向主动回避和被动回避）来解决对硫磷在低水平长期暴露后是否会损害认知功能并可能导致认知持续变化的问题。运动活动和一般行为在功能观察电池中进行了调查。在大鼠食物中低剂量给予对硫磷，无临床症状，无或边缘性脑乙酰胆碱酯酶抑制。在第13周，在大鼠食物中添加0.5、2或8 ppm的对硫磷，每组雄性大鼠每天平均摄取24、100或400 μ g/kg体重，雌性大鼠每天平均摄取36、152或550 μ g/kg体重。在治疗结束后的第1 - 4周、第10 - 14周以及第30 - 34周，当雄性和雌性大鼠大约13个月大时，进行学习测试。在任何测试中，无论是在治疗期间还是在延长的无治疗期之后，每天给予低剂量对硫磷13周，对学习和记忆都没有累积或不良影响。在治疗的第一周（雄性剂量组0.5 ppm），在Morris水迷宫I中观察到与对照组相比，学习能力有显著改善，这表明对硫磷可以改善大鼠的认知功能。研究结果表明，改变动物学习和记忆的不良影响可能只发生在较高剂量的有机磷酸酯中，在这种情况下，外周和大脑乙酰胆碱酯酶被抑制的程度比本研究中的程度更大，(C) 1998 Society of Toxicology。
A set of four learning and memory tests (Morris Maze I for reference memory, Morris Maze II for working memory, one-way active avoidance, and passive avoidance) were employed to address the questions whether parathion impaired cognitive functions after low, long-term exposure and could cause persistent changes in cognition. Motor activity and general behavior were investigated in a functional observational battery. Parathion was administered in rat food in low doses which caused no clinical symptoms and no or borderline brain acetylcholinesterase inhibition. Parathion doses of 0.5, 2, or 8 ppm in rat food produced the averaged uptake of 24, 100, or 400 mu g/kg body weight per group per day in male rats and 36, 152, or 550 mu g/kg per day in female rats in week 13. Learning tests were performed in weeks 1 to 4 and 10 to 14, as well as 30 to 34 weeks after the end of treatment, when the male and female rats were about 13 months old. Low doses of parathion given daily for 13 weeks had no cumulative or adverse effects on learning and memory, either during treatment or after the extended treatment-free period, in any of the tests. A significant improvement of learning compared to control observed in the Morris Water Maze I during the first week of treatment (males dose group 0.5 ppm) shows that parathion can improved cognitive functions in rats. Results of the study indicate that adverse effects changing learning and memory in animals may occur only at higher doses of organophosphates, at which the peripheral and brain acetylcholinesterases are inhibited to a greater extent than those in the present study, (C) 1998 Society of Toxicology.