Scholz Nathaniel L, Truelove Nathan K, Labenia Jana S, Baldwin David H, Collier Tracy K
National Oceanic and Atmospheric Administration, Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, Washington 98112, USA.
Environ Toxicol Chem. 2006 May;25(5):1200-7. doi: 10.1897/05-030r1.1.
Organophosphate and carbamate insecticides are widely detected in surface waters of the western United States. These chemicals interfere with acetylcholine-mediated synaptic transmission in the nervous systems of fish and other aquatic animals via the inhibition of AChE (acetylcholinesterase) enzyme activity. Anticholinesterase insecticides commonly co-occur in the environment. This raises the possibility of antagonistic, additive, or synergistic neurotoxicity in exposed fish, including threatened and endangered species of Pacific salmon. We extracted AChE from the olfactory nervous system of chinook salmon (Oncorhynchus tshawytscha) and investigated the inhibitory effects of organophosphates (the oxon derivatives of diazinon, chlorpyrifos, and malathion) and carbamates (carbaryl and carbofuran), alone and in two-way combinations. We found that the joint toxicity of anticholinesterase mixtures can be accurately predicted from the inhibitory potencies of individual chemicals within a mixture. This indicates that organophosphate and carbamate insecticides are noninteractive in terms of AChE inhibition and that it might be possible to estimate the cumulative neurotoxicity of mixtures by simple dose addition. Because organophosphates and carbamates are likely to have additive effects on the neurobehavior of salmon under natural exposure conditions, ecological risk assessments that focus on individual anticholinesterases might underestimate the actual risk to salmon in watersheds in which mixtures of these chemicals occur.
在美国西部的地表水中广泛检测到有机磷酸酯和氨基甲酸酯类杀虫剂。这些化学物质通过抑制乙酰胆碱酯酶（AChE）的酶活性，干扰鱼类和其他水生动物神经系统中乙酰胆碱介导的突触传递。抗胆碱酯酶杀虫剂在环境中通常同时存在。这增加了暴露鱼类（包括太平洋鲑鱼的受威胁和濒危物种）出现拮抗、相加或协同神经毒性的可能性。我们从奇努克鲑鱼（Oncorhynchus tshawytscha）的嗅觉神经系统中提取了乙酰胆碱酯酶，并研究了有机磷酸酯（二嗪农、毒死蜱和马拉硫磷的氧代衍生物）和氨基甲酸酯（西维因和克百威）单独以及两两组合的抑制作用。我们发现，抗胆碱酯酶混合物的联合毒性可以根据混合物中各单一化学物质的抑制效力准确预测。这表明有机磷酸酯和氨基甲酸酯类杀虫剂在抑制乙酰胆碱酯酶方面不具有相互作用，并且有可能通过简单的剂量相加来估计混合物的累积神经毒性。由于在自然暴露条件下，有机磷酸酯和氨基甲酸酯类可能对鲑鱼的神经行为产生相加作用，因此专注于单一抗胆碱酯酶的生态风险评估可能会低估这些化学物质混合物存在的流域中鲑鱼面临的实际风险。
