最新乙酰胆碱受体杀虫剂药理学教学讲义ppt.ppt

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1、乙酰胆碱受体杀虫剂药理学1.nerveimpulsearrives2.voltage-gatedCa2+channelsopen3.Synapticvesiclesfusewithplasmamembraneanddumpcontents4.SignallingmoleculecausesresponseinpostsynapticmembraneSequenceofevents2二、氯化烟酰、沙蚕毒素类杀虫剂3Nicotine,intheformoftobaccoextract,hasbeenusedasaninsecticidesincethemid-eighteen

2、thcenturyandstillranksasanexcellentcontactinsecticide.PlantinsecticideBotanicalinsecticide1Nicotine7Nicotineattacksacetylcholinereceptors,whichresemblecholinesterases.Nicotineselectivelyattackstheneuromuscularjunctionofmammalsandthesynapticganglionofinsectswithoutseverelyattackingotherkno

3、wnacetylcholinereceptors.1Nicotine8Nicotine↓AChR(acetylcholinereceptor)↓SodiumChannelOpen↓SodiumInflux↓NerveImpulse1Nicotine9Themostconspicuousfeatureofnicotinepoisoningininsectsisitsselectiveinhibitoryactionsonnervegangliaandsynapses.Itappearsthatnicotineisveryselectiveinchoosingthebindi

4、ngsitesinbothinsectsandmammals.1Nicotine10Nicotineselectivelyattackstheneuromuscularjunctionofmammalsandthesynapticgangliaofinsectswithoutseverelyattackingotherknownacetylcholinereceptorsortheacetylcholinesterase,whichisknowntobesimilarinproteinstructuretotheacetylcholinereceptors.1Nicoti

5、ne11Nicotinecanmimictheactionofacetylcholineinvivoundertheproperconditions.Itislikelythatthereceptorssusceptibletonicotinecannotdistinguishbetweenacetylcholineandnicotine.1Nicotine12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

6、，故残效期较短，而它的盐类（如硫酸烟碱）则较稳定，残效期长。1Nicotine132Imidacloprid(吡虫啉)Chloronicotinylinsecticide(氯化烟酰类杀虫剂)Becauseofhighmammaliantoxicityandrelativelylowinsecticidalactivitynicotineitselfhasnotbeenwidelyusedasapesticidesincethe1940s.142Imidacloprid(吡虫啉)Beginningwithnithiazinein1979somerelatedsyntheti

7、csubstancereactingatthesamereceptorasnicotinewerediscovered.Imidaclopridwasintroducedin1992asanewneonicotinoidinsecticides.152Imidacloprid(吡虫啉)Imidaclopridhassimilaritiestonicotineandacomparablemodeofaction.Itisactiveagainstsuckinginsectsbecauseoftheuniqueplant-syst