乙酰膽堿受體殺蟲劑藥理學(xué)第一頁，共25頁。1.nerveimpulsearrives2.voltage-gatedCa2+channelsopen3.Synapticvesiclesfusewithplasmamembraneanddumpcontents4.SignallingmoleculecausesresponseinpostsynapticmembraneSequenceofevents2第二頁，共25頁。二、氯化煙酰、沙蠶毒素類殺蟲劑

3第三頁，共25頁。作用于乙酰膽堿受體的殺蟲劑

4第四頁，共25頁。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(dǎo)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(dǎo)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(dǎo)致某些疾病的發(fā)生。5第五頁，共25頁。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(xué)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(xué)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。

6第六頁，共25頁。Nicotine,intheformoftobaccoextract,hasbeenusedasaninsecticidesincethemid-eighteenthcenturyandstillranksasanexcellentcontactinsecticide.PlantinsecticideBotanicalinsecticide1Nicotine7第七頁，共25頁。Nicotineattacksacetylcholinereceptors,whichresemblecholinesterases.Nicotineselectivelyattackstheneuromuscularjunctionofmammalsandthesynapticganglionofinsectswithoutseverelyattackingotherknownacetylcholinereceptors.1Nicotine8第八頁，共25頁。Nicotine↓AChR(acetylcholinereceptor)↓SodiumChannelOpen↓SodiumInflux↓NerveImpulse1Nicotine9第九頁，共25頁。Themostconspicuousfeatureofnicotinepoisoningininsectsisitsselectiveinhibitoryactionsonnervegangliaandsynapses.Itappearsthatnicotineisveryselectiveinchoosingthebindingsitesinbothinsectsandmammals.1Nicotine10第十頁，共25頁。Nicotineselectivelyattackstheneuromuscularjunctionofmammalsandthesynapticgangliaofinsectswithoutseverelyattackingotherknownacetylcholinereceptorsortheacetylcholinesterase,whichisknowntobesimilarinproteinstructuretotheacetylcholinereceptors.1Nicotine11第十一頁，共25頁。Nicotinecanmimictheactionofacetylcholineinvivoundertheproperconditions.Itislikelythatthereceptorssusceptibletonicotinecannotdistinguishbetweenacetylcholineandnicotine.1Nicotine12第十二頁，共25頁。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）則較穩(wěn)定，殘效期長。1Nicotine13第十三頁，共25頁。2Imidacloprid(吡蟲啉)Chloronicotinylinsecticide(氯化煙酰類殺蟲劑)Becauseofhighmammaliantoxicityandrelativelylowinsecticidalactivitynicotineitselfhasnotbeenwidelyusedasapesticidesincethe1940s.14第十四頁，共25頁。2Imidacloprid(吡蟲啉)Beginningwithnithiazinein1979somerelatedsyntheticsubstancereactingatthesamereceptorasnicotinewerediscovered.Imidaclopridwasintroducedin1992asanewneonicotinoidinsecticides.15第十五頁，共25頁。2Imidacloprid(吡蟲啉)Imidaclopridhassimilaritiestonicotineandacomparablemodeofaction.Itisactiveagainstsuckinginsectsbecauseoftheuniqueplant-systemicandtranslaminarproperties.16第十六頁，共25頁。2Imidacloprid(吡蟲啉)ModeofactionItappearsthatimidaclopridactsinawaythatiscomparabletotheactionofacetylcholineonspecificnervecell.Thefavorableselectivetoxicityofimidaclopridtoinsectsversusmammalsisattributedtodifferencesintheirbindingaffinityorpotencyinthenicotinicacetylcholinereceptor.17第十七頁，共25頁。2Imidacloprid(吡蟲啉)ModeofactionItappearsthatthisbinding-sitespecificityforimidaclopriddependsinlargepartonmajorstructuraldifferencesintheneuronalnicotinicacetylcholinereceptorbindingsitesofmammalsandinsects.18第十八頁，共25頁。2Imidacloprid(吡蟲啉)ModeofactionThisselectivityofthechloronicotinylcompoundsforinsectsasopposedtomammalscanbepartlyexplainedbydifferencesintheionizationofthepyrolidinenitrogen.Imidaclopridispoorlyionizedintheneutralmedia,incontrasttonicotine,andthuspasseseasilythroughinsectlipophilicbarriers.19第十九頁，共25頁。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(dǎo)三種功能，使害蟲中樞神經(jīng)阻斷麻痹后迅速死亡。

無交叉抗性，對人畜安全，能有效保護天敵。2Imidacloprid(吡蟲啉)20第二十頁，共25頁。AnimaltoxicityImidaclopridexhibitsmoderatelyacuteoraltoxicitytomammalswithLD50valuesofapproximately450and150mg/kgbwinratandmice,respectively.Mutagenicitytestswerenegative.2Imidacloprid(吡蟲啉)21第二十一頁，共25頁。1934年日本人從沙蠶中分離出沙蠶毒素（