有机磷类杀虫剂存在其他作用靶分子

Other Target Molecule of Some Organophosphorus Insecticides(OPs)

目的:研究有机磷类杀虫剂对大鼠脑G蛋白偶联受体激酶2介导的毒蕈碱乙酰胆碱m2受体磷酸化的影响,揭示有机磷类杀虫剂存在的其他作用靶分子或作用途径。方法:制备亲和层析柱;利用亲和层析方法从大鼠脑中纯化毒蕈碱乙酰胆碱m2受体;将纯化的毒蕈碱乙酰胆碱m2受体或β-肾上腺素受体,G蛋白偶联受体激酶-2,[γ-p32]ATP与对氧磷(PO)、氧毒死蜱(CPO)共同保温,聚丙烯酰胺凝胶电泳分离蛋白,放射性自显影检测m2受体磷酸化结果。结果:氧毒死蜱完全抑制大鼠脑m2受体的磷酸化,其半数抑制浓度为(IC50)70μmol/L;对氧磷不抑制m2受体的磷酸化;氧毒死蜱和对氧磷都不抑制β-肾上腺素受体的磷酸化。结论:氧毒死蜱有选择性地抑制大鼠脑m2受体的磷酸化,说明某些有机磷杀虫剂的毒性作用存在其他靶分子或作用途径。

Objective： To explore the other target molecule of organophosphorus insecticides（OPs） in vitro and to understand alternative target of the OPs for human and other animals. Methods： The muscarinic acetylcholine m2 receptors were purified from rat brain by single step affinity chromatography. In vitro experiments, purified m2 receptor or β-adrenergic receptor were incubated with varying concentration of paraoxon, chlopyrifos oxon along with G-protein coupled receptor kinase 2 （GRK2）and [ γ-P^32 ] ATP. Proteins were separated by electrophoresis, gels were dried and autoradioprams were developed. Results： Chlopyrifos oxon inhibited phosphorylation of m2 muscarinic receptors by GRK2 with an IC50 of approximately 70 μM, paraoxon had little effect on the receptor phosphorylation under the same conditions. Both Chlopyrifos oxon and chlopyrifos did not inhibit phosphorylation of β-adrenergic receptor. Conclusion. Chlopyrifos oxon alters GRK2-mediated regulatory pathways for m2 receptors by direct interaction with m2 receptor. These differential actions could contribute to existence of the other target molecule of some OPs.