乙酰膽堿受體殺蟲劑藥理學

乙酰膽堿受體殺蟲劑藥理學乙酰膽堿受體殺蟲劑藥理學乙酰膽堿受體殺蟲劑藥理學1.nerveimpulsearrives2.voltage-gatedCa2+channelsopen3.Synapticvesiclesfusewithplasmamembraneanddumpcontents4.SignallingmoleculecausesresponseinpostsynapticmembraneSequenceofevents2021/11/1421.nerveimpulsearrives

2.voltage-gatedCa2+channelsopen3.Synapticvesiclesfusewithplasmamembraneanddumpcontents4.SignallingmoleculecausesresponseinpostsynapticmembraneSequenceofevents2021/11/142二、氯化煙酰、沙蠶毒素類殺蟲劑

2021/11/143作用于乙酰膽堿受體的殺蟲劑

2021/11/144作用于乙酰膽堿受體的殺蟲劑乙酰膽堿受體是一種神經(jīng)遞質(zhì)介導的離子通道受體，由5個同源亞基組成。乙酰膽堿

受體包括肌肉型和神經(jīng)型兩種。肌肉型乙酰膽堿受體是肌肉神經(jīng)傳導中的重要媒介物質(zhì)以及自身免疫疾病重癥肌無力的主要免疫原,

神經(jīng)型乙酰膽堿受體的突變也可導致某些疾病的發(fā)生。2021/11/145作用于乙酰膽堿受體的殺蟲劑尼古丁之所以會讓人上癮，是因為它模仿某種使人覺得愉快的化學物質(zhì)——乙酰膽堿，“劫持〞了大腦中與乙酰膽堿結(jié)合的受體蛋白質(zhì)。乙酰膽堿受體可以分為多個亞單位，科學家已經(jīng)發(fā)現(xiàn)了12個這樣的亞單位。一個稱為a4*的乙酰膽堿受體亞單位在尼古丁成癮過程中起到關(guān)鍵作用。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本劑為植物源殺蟲劑，其有效殺蟲成分為由煙草中提取的煙堿。純品為無色油狀液體，性質(zhì)不穩(wěn)定。易揮發(fā)，能溶于水和有機溶劑。遇光和空氣易變成褐色，有奇臭味和強烈刺激性。對害蟲有胃毒、觸殺和熏蒸作用，還有殺卵作用。煙堿易揮發(fā)，故殘效期較短，而它的鹽類〔如硫酸煙堿〕那么較穩(wěn)定，殘效期長。1Nicotine2021/11/14132Imidacloprid(吡蟲啉)Chloronicotinylinsecticide(氯化煙酰類殺蟲劑)Becauseofhighmammaliantoxicityandrelativelylowinsecticidalactivitynicotineitselfhasnotbeenwidelyusedasapesticidesincethe1940s.2021/11/14142Imidacloprid(吡蟲啉)Beginningwithnithiazinein1979somerelatedsyntheticsubstancereactingatthesamereceptorasnicotinewerediscovered.Imidaclopridwasintroducedin1992asanewneonicotinoidinsecticides.2021/11/14152Imidacloprid(吡蟲啉)Imidaclopridhassimilaritiestonicotineandacomparablemodeofaction.Itisactiveagainstsuckinginsectsbecauseoftheuniqueplant-systemicandtranslaminarproperties.2021/11/14162Imidacloprid(吡蟲啉)ModeofactionItappearsthatimidaclopridactsinawaythatiscomparabletotheactionofacetylcholineonspecificnervecell.Thefavorableselectivetoxicityofimidaclopridtoinsectsversusmammalsisattributedtodifferencesintheirbindingaffinityorpotencyinthenicotinicacetylcholinereceptor.2021/11/14172Imidacloprid(吡蟲啉)ModeofactionItappearsthatthisbinding-sitespecificityforimidaclopriddependsinlargepartonmajorstructuraldifferencesintheneuronalnicotinicacetylcholinereceptorbindingsitesofmammalsandinsects.2021/11/14182Imidacloprid(吡蟲啉)ModeofactionThisselectivityofthechloronicotinylcompoundsforinsectsasopposedtomammalscanbepartlyexplainedbydifferencesintheionizationofthepyrolidinenitrogen.Imidaclopridispoorlyionizedintheneutralmedia,incontrasttonicotine,andthuspasseseasilythroughinsectlipophilicbarriers.2021/11/1419吡蟲啉特點：

超高效、低毒、廣譜，對各類蚜蟲有特效。藥后3天防效達98%。持效期長，可達30天以上。

適用范圍廣，用藥量低。

殺蟲機理獨特，同時具備觸殺、胃毒、內(nèi)吸傳導三種功能，使害蟲中樞神經(jīng)阻斷麻痹后迅速死亡。

無穿插抗性，對人畜平安，能有效保護天敵。2Imidacloprid(吡蟲啉)2021/11/1420AnimaltoxicityImidaclopridexhibitsmoderatelyacuteoraltoxicitytomammalswithLD50valuesofapproximately450and150mg/kgbwinratandmice,respectively.Mutagenicitytestswerenegative.2Imidacloprid(吡蟲啉)2021/11/14211934年日本人從沙蠶中別離出沙蠶毒素〔Nereistoxin〕，1962年確定其化學構(gòu)造：3沙蠶