有机磷类杀虫剂对脑突触体烟碱型自主受体功能的影响

Effect of paraoxon and chlorpyrifos on the nicotinic autoreceptor function in rat cortical synaptosomes

目的 探讨有机磷杀虫剂 (OPs)对脑突触体烟碱型自主受体功能 (NAF)的影响 ,揭示OPs可能存在的其他作用途径。方法 (1)体外实验 :以放射性核素氚标记的胆碱与大鼠脑突触体共同温育后用生理缓冲液灌流 ,根据不同有机磷刺激时的放射性胆碱释放量计算NAF值 ,分析氧毒死蜱和对氧磷分别加入灌流系统后NAF的变化 ;(2 )体内实验 :用毒死蜱给大鼠染毒 ,96h后取其大脑皮质制备突触体 ,测定其NAF和乙酰胆碱酯酶 (AChE)活力。结果 对氧磷在体外对NAF影响较小(平均抑制率 <2 3% ) ,但氧毒死蜱却彻底抑制NAF(平均抑制率 >10 0 % )。体内实验亦显示 ,毒死蜱在抑制AChE活力 (抑制率为 91% )的同时 ,对NAF有较强的阻断作用 (抑制率为 6 6 % )。结论 不同的OPs对脑突触体NAF的作用不同 ,毒死蜱可阻断成年大鼠脑突触体的NAF。

Objective To explore the effect of organophosphorus insecticides(OPs) on the nicotinic autoreceptor function(NAF) in rat cortical synaptosomes and to understand alternative target of the OPs for human and other animals. Methods In vitro experiment,synaptosomes from the rats were incubated with choline and then superfused with physiological buffer.The acetylcholine release from the synaptosomes after the addition of paraoxon or chlorpyrifos to the superfusion system was recorded and the changes of NAF were calculated.In vivo experiment,NAF and acetylcholinesterase(AChE) activity in the cortical synaptosomes in the adult rats dosed with chlorpyrifos were also determined 96 h after OPs treatment. Results Paraoxon caused slight effect on NAF(average inhibition rate:<23%) while chlorpyrifos oxon caused >100% of inhibition on NAF in vitro.Chlorpyrifos markedly reduced NAF by 66% 96 h after treatment and inhibited the AChE activity by 91% in vivo. Conclusion The OPs may have different effects on the NAF of rat cortical synaptosomes while chlorpyrifos may certainly inhibit the NAF in cortical synaptosomes of adult rats.