敌敌畏、甲基对硫磷小鼠LD_(50)测定及致死时间的量-效分析

按随机分组灌胃法测定小鼠敌敌畏(DDVP)和甲基对硫磷(M P)的LD_(50)±L_(95)(斜率)为337±77(6.5291)和105±38(3.7481)m g·kg~(-1),两者对比P<0.001.观察DDVP(ig)的致死时间发现是剂量依赖性(P<0.05).其双曲线型四参数模型Ⅱ的拟合方程为;(?)=41.9206/(InX—4.5681)~(3.2743)+2.8916.DDVP2000 mg·kg~(-1)剂量组的致死时间为4.0±0min(n=6).而MP4500 mg·kg~(-1)剂量组为10.3±5.2 min(n=6)。结果表明DDVP致小鼠死亡作用存在双曲线型时反应量—效关系.且毒性的时间强度高于MP。

LD_(50)and dose-lethal time analyses of dichlorvos and methyl parathion on mice

The LD50 and lethal time of dichlorvos (DDVP) and methyl parathion(MP) by ig were studied in the mice. The LD50 ± L95 (slope) of DDVP and MP calculated by Bliss method was 337 ± 77(6. 5291) and 105 ±38 (3.7481) mg · kg-1] respectively, in which Us is the average confidence Limit of 95%,The comparison of two LD50 showed very significant difference (P<0. 001). It was also found that the lethal time of mice was significantly DDVP dose - dependent ( P < 0. 05 ) and the dose -lethal time data were nonlinear Least-square fit to the hyperbolic four - parameter model, weighting the square error inversely with the square of SE. From the regression equation Y= 41. 9206/(lnX - 4. 5681 )3.2743 + 2. 8916, in which Y is the lethal time and X dose of DDVP, the shortest, LD50 and LD10 lethal time were calculated to be 3,23and 91 min. Specially the average lethal time at dosage of 2000 mg · kg-1of DDVP was 4. 0±0 min (n = 6) ,but at 4500 mg · kg-1 of MP was 10. 3±5. 2 min (n = 6).The results indicate that the timed dose-response relationship exists in the lethal effect of DDVP on mice and the lethal time of DDVP is shorter than MP.but the LD50 higher.