Abstract

Organophosphates can damage the brain in systemic intoxication. In this study, the effects of a minimum toxic dose (MTD) of diazinon (DZ) on amygdala afterdischarge threshold (ADT), kindling acquisition and kindled seizure parameters were evaluated. Intact male rats were stereotactically implanted with a tripolar and two monopolar electrodes in the amygdala and dura respectively. After recovery, animals received daily either, olive oil (control), 15 or 30 mg/kg (MTD) of DZ intraperitoneally, and ADT, afterdischarge duration (ADD) at each stage (S₁ to S₅) of kindling and number of trials for kindling acquisition were determined daily. Also, the effect of DZ on stage 4 latency (S₄L), ADD, stage 5 duration (S₅D) and the activity of the red blood cholinesterase (ChE) were evaluated. The ADT was lower and the ADD was longer significantly in DZ treated group in comparison to control (p < 0.01) and the number of trials to reach each stage of kindling acquisition was reduced (p < 0.001). The total amount of ADDs during the kindling procedure increased significantly 5 days after DZ treatment. While the S₄L was reduced, the S₅D increased significantly after DZ treatment. The ChE activity was inhibited significantly after 20 min of DZ treatment and continued till 24 h (p < 0.01). Data indicate that even half of the MTD of DZ could increase the sensitivity and excitability of the CNS to the epileptic activity at least via reduction of stimulation threshold and AD prolongation. Furthermore, repeated exposure to the low concentrations of organophosphates may be pro-convulsant and should be restricted.

摘要

有机磷酸盐会在全身中毒时损害大脑。在这项研究中，评估了二嗪农 (DZ) 的最小毒性剂量 (MTD) 对杏仁核后放电阈值 (ADT)、点燃采集和点燃癫痫发作参数的影响。完整的雄性大鼠分别在杏仁核和硬脑膜中立体定向植入一个三极和两个单极电极。恢复后，动物每天接受橄榄油（对照）、15 或 30 mg/kg (MTD) 的 DZ 腹膜内注射，以及 ADT、每个点燃阶段 (S ₁至 S ₅ ) 的后放电持续时间 (ADD) 和数量每天确定获取引种的试验。此外，DZ 对第 4 阶段潜伏期 (S ₄ L)、ADD、第 5 阶段持续时间 (S ₅D)和红血胆碱酯酶(ChE)的活性进行了评价。与对照组相比，DZ 治疗组的 ADT 较低且 ADD 较长（p  < 0.01），并且达到点燃获得每个阶段的试验次数减少（p  < 0.001）。在 DZ 处理后 5 天，点燃过程中的 ADD 总量显着增加。在S ₄ L 降低的同时，DZ 处理后S ₅ D 显着增加。DZ 处理 20 分钟后，ChE 活性被显着抑制并持续至 24 小时（p < 0.01)。数据表明，即使是 DZ 的一半 MTD 至少可以通过降低刺激阈值和延长 AD 来增加 CNS 对癫痫活动的敏感性和兴奋性。此外，反复接触低浓度的有机磷酸盐可能会诱发惊厥，应加以限制。