Learning behavior in rat offspring after, in utero and lactational exposure to either TCDD or PCB126
Learning behavior in rat offspring after, in utero and lactational exposure to either TCDD or PCB126
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DOI：
10.1007/s12199-008-0026-0
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发表时间：
2008-05-01
影响因子：
4.7
通讯作者：
Tohyama, Chiharu
中科院分区：
文献类型：
--
作者：
Hojo, Rieko;Kakeyama, Masaki;Tohyama, Chiharu
目的研究和比较子宫和哺乳期接触2，3，7，8-四氯二苯并-对二恶英(TCDD)和3，3‘，4，4’，5-四氯联苯(PCB126)对仔鼠学习行为的影响。采用固定比率应答率、低应答率差别化强化应答率和多次FR20DRL20 S(MULT-FR20DRL20-S)试验中低应答率成分的奖励率3项指标对学习行为进行评价。然而，对于上述三个指标，两种化合物都没有观察到线性的剂量依赖效应。低剂量TCDD和PCB126组动物反应率下降，中剂量TCDD和PCB126组动物出现多动行为。结论PCB126和TCDD对学习行为的毒性可能相似，目前PCB126的毒性当量系数(TEF)为0.1是比较合适的。
Objectives We studied and compared the possible effects of in Utero and lactational exposure to 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) or 3, 3', 4, 4', 5-pen tachlorobiphenyl (PCB126) on learning behavior in offspring.Methods Pregnant Long-Evans Hooded rats were administered either TCDD (50, 200, or 800 ng/kg) or PCB 126 (500, 2,000 or 8,000 ng/kg) on gestational day 15. A procedure of schedule-controlled operant behavior was applied to examine learning behavior in the male and female offspring at 11 weeks of age for 30 days. Three indices, namely, response rates in a fixed ratio (FR) and in a differential reinforcement of low rates (DRL), and reward rate in the DRL component in multiple FR 20 DRL 20 s (mult-FR 20 DRL 20-s) test sessions, were used for the evaluation of learning behavior.Results Toxic effects on learning behavior in male and female pups following in utero and lactational exposure to TCDD or PCB126 were observed mainly in the FR learning component. However, no linear dose-dependent effects of either of the two compounds were observed for the above three indices. The response rates of animals in the low-dose TCDD and PCB126 groups decreased and those in medium-dose TCDD and PCB126 groups appeared to induce hyperactive behavior. The high dose of PCB126 appeared to have a distinct toxicity from that of TCDD in terms of the acquisition of learning behavior.Conclusions Toxicities of PCB126 and TCDD in learning behavior might be similar to each other and the current toxic equivalency factor (TEF) of 0.1 for PCB126 can be considered to be appropriate for this endpoint.