Department of Plant and Environmental Protection Sciences, 402 Gilmore Hall, University of Hawaii, Honolulu, HI 96822, US.
Environ Toxicol Pharmacol. 2005 Jul;20(1):18-21. doi: 10.1016/j.etap.2004.09.011. Epub 2004 Dec 7.
We investigated interactions of the neonicotinoid insecticide imidacloprid with the nicotinic acetylcholine-regulated receptors (nAcChR) of embryonic frog muscle cells. The response of the muscle cells to acetylcholine, nicotine and imidacloprid was monitored as cell contractions. Acetylcholine was more potent than nicotine (EC(50)=5×10(-8)M versus 6×10(-7)M) in this physiological test system. Contractions induced by acetylcholine or nicotine were both blocked by α-bungarotoxin (IC(50)=9×10(-7)M). Imidacloprid itself did not cause cell contractions but at concentrations ≥3.3×10(-6)M prevented or attenuated those induced by acetylcholine (5×10(-7)M and 5×10(-5)M) or nicotine (5×10(-6)M to 5×10(-3)M). The dose response relationship between acetylcholine or nicotine, imidacloprid and cell contractions suggests that imidacloprid is an antagonist at the nAcChR of the muscle cells in contrast to its established role as an agonist in its toxic action on insect neural receptors. In chicken embryos, imidacloprid caused arthrogryposis, presumably due to its interference with the embryonic neuromuscular nAcChR. A magnitude of imidacloprid dose that caused arthrogryposis indicates a negligible teratogenic potential of imidacloprid when applied for the insect pest control.
我们研究了新烟碱类杀虫剂吡虫啉与胚胎青蛙肌肉细胞烟碱型乙酰胆碱受体（nAcChR）的相互作用。肌肉细胞对乙酰胆碱、尼古丁和吡虫啉的反应通过细胞收缩来监测。在这个生理测试系统中，乙酰胆碱比尼古丁更有效（EC（50）=5×10（-8）M 对 6×10（-7）M）。乙酰胆碱或尼古丁诱导的收缩均被α-银环蛇毒素（IC（50）=9×10（-7）M）阻断。吡虫啉本身不会引起细胞收缩，但在浓度≥3.3×10（-6）M 时，可预防或减弱由乙酰胆碱（5×10（-7）M 和 5×10（-5）M）或尼古丁（5×10（-6）M 至 5×10（-3）M）诱导的收缩。乙酰胆碱或尼古丁、吡虫啉与细胞收缩之间的剂量反应关系表明，吡虫啉是肌肉细胞 nAcChR 的拮抗剂，与它在昆虫神经受体的毒性作用中作为激动剂的既定作用相反。在鸡胚胎中，吡虫啉引起关节弯曲，可能是由于其干扰了胚胎神经肌肉 nAcChR。引起关节弯曲的吡虫啉剂量表明，当用于防治害虫时，吡虫啉的致畸潜力可忽略不计。
