乙酰胆碱受体杀虫剂药理学

乙酰胆碱受体杀虫剂药理学乙酰胆碱受体杀虫剂药理学乙酰胆碱受体杀虫剂药理学1.nerveimpulsearrives2.voltage-gatedCa2+channelsopen3.Synapticvesiclesfusewithplasmamembraneanddumpcontents4.SignallingmoleculecausesresponseinpostsynapticmembraneSequenceofevents2021/11/1421.nerveimpulsearrives

2.voltage-gatedCa2+channelsopen3.Synapticvesiclesfusewithplasmamembraneanddumpcontents4.SignallingmoleculecausesresponseinpostsynapticmembraneSequenceofevents2021/11/142二、氯化烟酰、沙蚕毒素类杀虫剂

2021/11/143作用于乙酰胆碱受体的杀虫剂

2021/11/144作用于乙酰胆碱受体的杀虫剂乙酰胆碱受体是一种神经递质介导的离子通道受体，由5个同源亚基组成。乙酰胆碱

受体包括肌肉型和神经型两种。肌肉型乙酰胆碱受体是肌肉神经传导中的重要媒介物质以及自身免疫疾病重症肌无力的主要免疫原,

神经型乙酰胆碱受体的突变也可导致某些疾病的发生。2021/11/145作用于乙酰胆碱受体的杀虫剂尼古丁之所以会让人上瘾，是因为它模仿某种使人觉得愉快的化学物质——乙酰胆碱，“劫持〞了大脑中与乙酰胆碱结合的受体蛋白质。乙酰胆碱受体可以分为多个亚单位，科学家已经发现了12个这样的亚单位。一个称为a4*的乙酰胆碱受体亚单位在尼古丁成瘾过程中起到关键作用。2021/11/146Nicotine,intheformoftobaccoextract,hasbeenusedasaninsecticidesincethemid-eighteenthcenturyandstillranksasanexcellentcontactinsecticide.PlantinsecticideBotanicalinsecticide1Nicotine2021/11/147Nicotineattacksacetylcholinereceptors,whichresemblecholinesterases.Nicotineselectivelyattackstheneuromuscularjunctionofmammalsandthesynapticganglionofinsectswithoutseverelyattackingotherknownacetylcholinereceptors.1Nicotine2021/11/148Nicotine↓AChR(acetylcholinereceptor)↓SodiumChannelOpen↓SodiumInflux↓NerveImpulse1Nicotine2021/11/149Themostconspicuousfeatureofnicotinepoisoningininsectsisitsselectiveinhibitoryactionsonnervegangliaandsynapses.Itappearsthatnicotineisveryselectiveinchoosingthebindingsitesinbothinsectsandmammals.1Nicotine2021/11/1410Nicotineselectivelyattackstheneuromuscularjunctionofmammalsandthesynapticgangliaofinsectswithoutseverelyattackingotherknownacetylcholinereceptorsortheacetylcholinesterase,whichisknowntobesimilarinproteinstructuretotheacetylcholinereceptors.1Nicotine2021/11/1411Nicotinecanmimictheactionofacetylcholineinvivoundertheproperconditions.Itislikelythatthereceptorssusceptibletonicotinecannotdistinguishbetweenacetylcholineandnicotine.1Nicotine2021/11/1412本剂为植物源杀虫剂，其有效杀虫成分为由烟草中提取的烟碱。纯品为无色油状液体，性质不稳定。易挥发，能溶于水和有机溶剂。遇光和空气易变成褐色，有奇臭味和强烈刺激性。对害虫有胃毒、触杀和熏蒸作用，还有杀卵作用。烟碱易挥发，故残效期较短，而它的盐类〔如硫酸烟碱〕那么较稳定，残效期长。1Nicotine2021/11/14132Imidacloprid(吡虫啉)Chloronicotinylinsecticide(氯化烟酰类杀虫剂)Becauseofhighmammaliantoxicityandrelativelylowinsecticidalactivitynicotineitselfhasnotbeenwidelyusedasapesticidesincethe1940s.2021/11/14142Imidacloprid(吡虫啉)Beginningwithnithiazinein1979somerelatedsyntheticsubstancereactingatthesamereceptorasnicotinewerediscovered.Imidaclopridwasintroducedin1992asanewneonicotinoidinsecticides.2021/11/14152Imidacloprid(吡虫啉)Imidaclopridhassimilaritiestonicotineandacomparablemodeofaction.Itisactiveagainstsuckinginsectsbecauseoftheuniqueplant-systemicandtranslaminarproperties.2021/11/14162Imidacloprid(吡虫啉)ModeofactionItappearsthatimidaclopridactsinawaythatiscomparabletotheactionofacetylcholineonspecificnervecell.Thefavorableselectivetoxicityofimidaclopridtoinsectsversusmammalsisattributedtodifferencesintheirbindingaffinityorpotencyinthenicotinicacetylcholinereceptor.2021/11/14172Imidacloprid(吡虫啉)ModeofactionItappearsthatthisbinding-sitespecificityforimidaclopriddependsinlargepartonmajorstructuraldifferencesintheneuronalnicotinicacetylcholinereceptorbindingsitesofmammalsandinsects.2021/11/14182Imidacloprid(吡虫啉)ModeofactionThisselectivityofthechloronicotinylcompoundsforinsectsasopposedtomammalscanbepartlyexplainedbydifferencesintheionizationofthepyrolidinenitrogen.Imidaclopridispoorlyionizedintheneutralmedia,incontrasttonicotine,andthuspasseseasilythroughinsectlipophilicbarriers.2021/11/1419吡虫啉特点：

超高效、低毒、广谱，对各类蚜虫有特效。药后3天防效达98%。持效期长，可达30天以上。

适用范围广，用药量低。

杀虫机理独特，同时具备触杀、胃毒、内吸传导三种功能，使害虫中枢神经阻断麻痹后迅速死亡。

无穿插抗性，对人畜平安，能有效保护天敌。2Imidacloprid(吡虫啉)2021/11/1420AnimaltoxicityImidaclopridexhibitsmoderatelyacuteoraltoxicitytomammalswithLD50valuesofapproximately450and150mg/kgbwinratandmice,respectively.Mutagenicitytestswerenegative.2Imidacloprid(吡虫啉)2021/11/14211934年日本人从沙蚕中别离出沙蚕毒素〔Nereistoxin〕，1962年确定其化学构造：3沙蚕