Martinez-Larrañaga María R, Anadón Arturo, Martínez Maria A, Martínez Marta, Castellano Victor J, Díaz María J
Department of Toxicology and Pharmacology, Faculty of Veterinary Medicine, Universidad Complutense de Madrid, 28040-Madrid, Spain.
Toxicol Ind Health. 2003 Oct;19(7-10):147-55. doi: 10.1191/0748233703th184oa.
Type II pyrethroids are a group of insecticides largely used in agriculture and public health. The nervous system is the main target for pyrethroids in insects and mammals. One notable form of toxicity associated with over exposure has been a facial cutaneous paraesthesia and irritation-related respiration symptoms including behavioural excitation mainly observed in workers spraying pyrethroids or in occupational settings. In acutely exposed rats, type II pyrethroids produce a severe syndrome characterized by salivation and choreoathetosis. Because many of the acute functional effects of type II pyrethoids can be associated with the neurotoxic effect on 5-hydroxytryptamine (5-HT) neurones, the objective of the present study was to examine whether deltamethrin, cyfluthrin and lambda-cyhalothrin administration results in changes of 5-HT content in rat brain. Characterizing this target will help us to better understand the toxicological effects of type II pyrethroids.
Rats were injected with either corn oil or pyrethroids (deltamethrin, 20 mg/kg per day, i.p., for 6 days; cyfluthrin, 14 mg/kg per day, i.p., for 6 days; lambda-cyhalothrin, 8 mg/kg per day, i.p., for 6 days). The frontal cortex, hippocampus, midbrain and striatum were removed at 24 hours post treatment and were analysed for content of 5-HT and 5-HIAA using a HPLC method with electrochemical detection.
A serotonin depleting effect was produced by these type II pyrethroids. The concentration of 5-HT and its metabolite 5-HIAA decreased in the brain regions from pyrethroid treated animals. Pyrethroids accelerated the turnover of 5-HT in midbrain and striatum areas. It is concluded that pyrethroids affect serotonin neurotransmission.
II型拟除虫菊酯是一类广泛应用于农业和公共卫生领域的杀虫剂。神经系统是拟除虫菊酯在昆虫和哺乳动物体内的主要作用靶点。与过度接触相关的一种显著毒性表现为面部皮肤感觉异常以及与刺激相关的呼吸症状，包括行为兴奋，主要见于喷洒拟除虫菊酯的工人或职业环境中。在急性暴露的大鼠中，II型拟除虫菊酯会引发一种以流涎和舞蹈手足徐动症为特征的严重综合征。由于II型拟除虫菊酯的许多急性功能效应可能与对5-羟色胺（5-HT）神经元的神经毒性作用有关，本研究的目的是检测给予溴氰菊酯、氟氯氰菊酯和高效氯氟氰菊酯是否会导致大鼠脑内5-HT含量的变化。明确这一靶点将有助于我们更好地理解II型拟除虫菊酯的毒理学效应。
给大鼠注射玉米油或拟除虫菊酯（溴氰菊酯，每天20mg/kg，腹腔注射，共6天；氟氯氰菊酯，每天14mg/kg，腹腔注射，共6天；高效氯氟氰菊酯，每天8mg/kg，腹腔注射，共6天）。在治疗后24小时取出额叶皮质、海马、中脑和纹状体，采用高效液相色谱电化学检测法分析5-HT和5-羟吲哚乙酸（5-HIAA）的含量。
这些II型拟除虫菊酯产生了5-羟色胺耗竭效应。经拟除虫菊酯处理的动物脑区中5-HT及其代谢产物5-HIAA的浓度降低。拟除虫菊酯加速了中脑和纹状体区域5-HT的周转。结论是拟除虫菊酯影响5-羟色胺神经传递。
