一些杀虫剂在达到环境相关浓度时会造成蜜蜂大脑神经功能失常。在Nature Communications上报告的这一发现为人们所观察到的蜜蜂觅食行为的中断和改变提供一个内在细胞机制。
杀虫剂在帮助维持作物产量上已被证明非常有效。然而，它们的使用被发现与很多昆虫数量的下降有关。新烟碱和有机磷酸酯是已被发现影响昆虫中枢神经系统中神经传输的两种类型的杀虫剂。蜜蜂为粮食生产提供必要的授粉作用，但这些杀虫剂对蜜蜂的具体影响却不清楚。Christopher Connolly及其同事获得了来自蜜蜂大脑中神经元的全部细胞记录，发现两种广泛使用的杀虫剂“吡虫啉”和“噻虫胺”通过激发烟碱受体损害神经元的可激发性。
本文作者得出的结论是，这一机制可解释蜜蜂接触特定杀虫剂后所发生的认知受损及其随后数量的下降。他们希望，这些发现将导致对于目标物种更有选择性的改进的害虫控制策略的出现。（生物谷Bioon.com）
Nature Communications, DOI:10.1038/ncomms2648
Cholinergic pesticides cause mushroom body neuronal inactivation in honeybees
Mary J. Palmer,Christopher Moffat,Nastja Saranzewa,Jenni Harvey,Geraldine A. Wright& Christopher N. Connolly
Pesticides that target cholinergic neurotransmission are highly effective, but their use has been implicated in insect pollinator population decline. Honeybees are exposed to two widely used classes of cholinergic pesticide: neonicotinoids (nicotinic receptor agonists) and organophosphate miticides (acetylcholinesterase inhibitors). Although sublethal levels of neonicotinoids are known to disrupt honeybee learning and behaviour, the neurophysiological basis of these effects has not been shown. Here, using recordings from mushroom body Kenyon cells in acutely isolated honeybee brain, we show that the neonicotinoids imidacloprid and clothianidin, and the organophosphate miticide coumaphos oxon, cause a depolarization-block of neuronal firing and inhibit nicotinic responses. These effects are observed at concentrations that are encountered by foraging honeybees and within the hive, and are additive with combined application. Our findings demonstrate a neuronal mechanism that may account for the cognitive impairments caused by neonicotinoids, and predict that exposure to multiple pesticides that target cholinergic signalling will cause enhanced toxicity to pollinators.
