乐果对大鼠大脑分区多巴胺神经递质的影响

目的观察乐果染毒对大鼠大脑分区单胺类神经递质多巴胺(DA)及其代谢物(DOPAC)浓度变化的影响。方法104只雄性SD大鼠随机分为对照组(生理盐水)和乐果染毒低(38.9mg/kg)、中(83.7mg/kg)、高(180.0mg/kg)3个剂量组,腹腔一次注射染毒,给药后0.5、2、8和24h断头处死并分离脑组织(大脑皮层、纹状体、海马、脑干和小脑5部分)。用正丁醇、正庚烷、高氯酸、三氯甲烷处理脑组织样品,用高效液相色谱电化学检测法检测。结果不同时程的染毒组(低、中、高剂量组)大脑DA浓度及其代谢物DOPAC与对照组相比差异均有显著性(P<0.05)。DA及其代谢物DOPAC在纹状体分别增加了28%~122%、89%~538%;DA在其它分区变化差异没有显著性。DOPAC在大脑皮层有的剂量和时程增加了50%~72%、有的剂量和时程减少了31%~51%;在海马差异没有显著性;在脑干有的剂量和时程增加了4%~102%、有的剂量和时程减少了10%~16%;在小脑有的剂量和时程增加了6%~39%、有的剂量和时程减少了6%~23%。DA和DOPAC浓度在不同时程的低、中、高剂量组间差异均有显著性(P<0.05)。结论DA和DOPAC浓度有随染毒剂量和时程的增加而增加的趋势,存在剂量-效应和时程-效应关系。因此乐果的中毒存在非胆碱能机制,多巴胺类能机制。

Effect of dimethoate on dopamines neurotransmitters in brain regions of rat

Objective To observe changes of dopamine and its metabolite (3,4-hydroxyphenylaceticacid, DOPAC) levels of the brain regions in rats exposed by dimethoate(DM). Methods Groups of rats were treated with saline and 38.9, 83.7 and 180.0mg/kg DM respectively, and were decapitated at different time course from 0.5 to 24 hours after the administration. The dopamine neurotransmitters and its metabolite were determined by reverse-phase high-performance liquid chromatography with electrochemical detection. Results The concentrations of DA(28%-122% of control)and DOPAC(89%-538% of control) varied according with the DM dose and the exposure time. Conclusion These results indicated that DM-induced toxic effects could alter the dopamine levels after the different dose and time exposure in the brain regions of rats.