Johnson Frank O, Chambers Janice E, Nail Carole A, Givaruangsawat Sumalee, Carr Russell L
Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39762, USA.
Toxicol Sci. 2009 May;109(1):132-42. doi: 10.1093/toxsci/kfp053. Epub 2009 Mar 17.
Although the use of organophosphate (OP) insecticides has been restricted, sufficient exposure can occur to induce detrimental neurobehavioral effects. In this study, we measured physical and reflex development and spatial learning and memory in rats repeatedly exposed to incremental doses of chlorpyrifos (CPS) and methyl parathion (MPS) from postnatal day (PND) 1 to PND21. Other than decreased body weight in the higher dosage groups, no effects on physical or reflex development were observed. Significant hippocampal cholinesterase inhibition was induced in all treatment groups for up to 19 days following exposure. Beginning on PND36, working and reference memory was tested using a 12-arm radial maze, with subject animals trained and tested 4 days a week for 4 weeks. In males, working memory was decreased with the medium and high dosage of MPS but only the high dosage of CPS; while in females, no deficits were observed. For reference memory, errors were significantly increased in males exposed to the high dosage of CPS and all dosages of MPS. In females, enhanced performance was observed within the medium and high dosages of CPS but not with MPS. These data show that repeated developmental exposure to OP insecticides can induce sex-selective alterations and long-lasting changes in spatial learning and memory formation when measured using a radial arm maze and that MPS and CPS induce different neurobehavioral outcomes.
尽管有机磷酸酯（OP）杀虫剂的使用已受到限制，但仍可能发生足够的接触，从而诱发有害的神经行为效应。在本研究中，我们测量了从出生后第1天（PND）到PND21反复接触递增剂量毒死蜱（CPS）和甲基对硫磷（MPS）的大鼠的身体和反射发育以及空间学习和记忆。除了较高剂量组的体重下降外，未观察到对身体或反射发育的影响。在所有治疗组中，接触后长达19天均诱导出显著的海马胆碱酯酶抑制。从PND36开始，使用12臂放射状迷宫测试工作记忆和参考记忆，受试动物每周训练和测试4天，共4周。在雄性中，中高剂量的MPS和仅高剂量的CPS会降低工作记忆；而在雌性中，未观察到缺陷。对于参考记忆，暴露于高剂量CPS和所有剂量MPS的雄性中的错误显著增加。在雌性中，在中高剂量的CPS组中观察到表现增强，但在MPS组中未观察到。这些数据表明，当使用放射状臂迷宫测量时，发育期间反复接触OP杀虫剂可诱导空间学习和记忆形成中的性别选择性改变和长期变化，并且MPS和CPS会诱导不同的神经行为结果。
