Developing Drugs from Traditional Medicinal Plants.doc

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1、DEVELOPINGDRUGSFROMTRADITIONALMEDICINALPLANTSOVERTHREEQUARTERSOFTHEWORLDSPOPULATIONRELIESMAINLYONPLANTSANDPLANTEXTRACTSFORHEALTHCAREAPPROXIMATELYONETHIRDOFTHEPRESCRIPTIONDRUGSINTHEUSCONTAINPLANTCOMPONENTS,ANDMORETHAN120IMPORTANTPRESCRIPTIONDRUGSAREDERIVEDFROMPLANTSMOSTOFTHESEDRUGSWEREDEVELOPEDBECAUS

2、EOFTHEIRUSEINTRADITIONALMEDICINEECONOMICALLY,THISREPRESENTS800010,000MOFANNUALCONSUMERSPENDINGRECENTWORLDHEALTHORGANIZATIONWHOSTUDIESINDICATETHATOVER30PERCENTOFTHEWORLDSPLANTSPECIESHAVEATONETIMEORANOTHERBEENUSEDFORMEDICINALPURPOSESOFTHE250,000HIGHERPLANTSPECIESONEARTH,MORETHAN80,000SPECIESAREMEDICIN

3、ALALTHOUGHTRADITIONALMEDICINEISWIDESPREADTHROUGHOUTTHEWORLD,ITISANINTEGRALPARTOFEACHINDIVIDUALCULTUREITSPRACTICEISBASEDMAINLYONTRADITIONALBELIEFSHANDEDDOWNFROMGENERATIONTOGENERATIONFORHUNDREDSOREVENTHOUSANDSOFYEARSUNFORTUNATELY,MUCHOFTHISANCIENTKNOWLEDGEANDMANYVALUABLEPLANTSAREBEINGLOSTATANALARMINGR

4、ATETHESCIENTIFICSTUDYOFTRADITIONALMEDICINESANDTHESYSTEMATICPRESERVATIONOFMEDICINALPLANTSARETHUSOFGREATIMPORTANCEFORQUITEALONGTIME,THEONLYWAYTOUSEPLANTMEDICINESWASEITHERDIRECTAPPLICATIONORTHEUSEOFCRUDEPLANTEXTRACTSWITHTHEDEVELOPMENTOFORGANICCHEMISTRYATTHEBEGINNINGOFTHISCENTURY,EXTRACTIONANDFRACTIONAT

5、IONTECHNIQUESIMPROVEDSIGNIFICANTLYITBECAMEPOSSIBLETOISOLATEANDIDENTIFYMANYOFTHEACTIVECHEMICALSFROMPLANTSINTHE1940S,ADVANCESINCHEMICALSYNTHESISENABLEDTHESYNTHESISOFMANYPLANTCOMPONENTSANDTHEIRDERIVATIVESINWESTERNCOUNTRIES,ITWASTHOUGHTTHATCHEMICALSYNTHESISOFDRUGSWOULDBEMOREEFFECTIVEANDECONOMICALTHANISO

6、LATIONFROMNATURALSOURCESINDEED,THISISTRUEINMANYCASESHOWEVER,INMANYOTHERCASES,SYNTHETICANALOGUESARENOTASEFFECTIVEASTHEIRNATURALCOUNTERPARTSINADDITIO,SOMESYNTHETICDRUGSCOSTMANYTIMESMORETHANNATURALONESINSPIREDBYTHESEREALISATIONS,COUPLEDWITHTHEFACTTHATMANYDRUGSWITHCOMPLEXSTRUCTURESMAYBETOTALLYIMPOSSIBLE

7、TOSYNTHESIS,THEREISNOWARESURGENTTRENDOFRETURNINGTONATURALRESOURCESFORDRUGDEVELOPMENTIMPORTANTPRESCRIPTIONDRUGSFROMPLANTSEPHEDRINEISTHEOLDESTANDMOSTCLASSICEXAMPLEOFAPRESCRIPTIONDRUGDEVELOPEDFROMATRADITIONALMEDICINALPLANTITISDERIVEDFROMMAHUANG,ALEAFLESSSHRUBUSEDTORELIEVEASTHMAANDHAYFEVERINCHINAFOROVER

8、5000YEARS,ITWASINTRODUCEDINTOWESTERNMEDICINEIN1924BYCHENANDSCHMIDTEPHEDRINEISANALKALOIDCLOSELYRELATEDTOADRENALINE,THEMAJORPRODUCTOFTHEADRENALGLANDPHARMACOLOGICALLY,EPHEDRINEISUSEDEXTENSIVELYTOSTIMULATEINCREASEDACTIVITYOFTHESYMPATHETICNERVOUSSYSTEMITISUSEDASAPRESSORAGENTTOCOUNTERACTHYPOTENSIONASSOCIA

9、TEDWITHANAESTHESIA,ANDASANASALDECONGESTANTTHEDRUGACTIONOFTHISMEDICINEISBASEDBOTHONITSDIRECTEFFECTONANDADRENERGICRECEPTORSANDONTHERELEASEOFENDOGENOUSNORADRENALINEDIGITALISISONEOFTHEMOSTFREQUENTLYUSEDMEDICATIONSINTHETREATMENTOFHEARTFAILUREANDARRHYTHMIAITINCREASESTHECONTRACTILITYOFTHEHEARTMUSCLEANDMODI

10、FIESVASCULARRESISTANCEITALSOSLOWSCONDUCTIONTHROUGHTHEATRIOVENTRICULARNODEINTHEHEART,MAKINGITUSEFULINTHETREATMENTOFATRIALFIBRILLATIONANDOTHERRAPIDHEARTRHYTHMSDIGITALISISFOUNDINTHELEAVESANDSEEDSOFDIGITALISPURPUREAANDDIGITALISLANATA,COMMONLYKNOWNASTHEFOXGLOVEPLANTFOXGLOVEHASBEENUSEDINTRADITIONALMEDICIN

11、EINMANYPARTSOFTHEWORLDBYAFRICANNATIVESASARROWPOISONS,BYTHEANCIENTEGYPTIANSASHEARTMEDICINE,ANDBYTHEROMANSASADIURETIC,HEARTTONIC,EMETICANDRATPOISONTHECHINESE,WHOFOUNDTHISINGREDIENTNOTONLYINPLANTSBUTALSOINTHEDRYSKINANDVENOMOFTHECOMMONTOAD,USEDITFORCENTURIESASACARDIACDRUGINTHEWESTERNWORLD,THEFOXGLOVEWAS

12、FIRSTMENTIONEDIN1250INTHEWRITINGOFAPHYSICIAN,WALSH,ANDITWASDESCRIBEDBOTANICALLYINTHE1500SDIGITALISISAGLYCOSIDECONTAININGANAGLYCONE,ORGENIN,LINKEDTOBETWEENONEANDFOURSUGARMOLECULESTHEPHARMACOLOGICALACTIVITYRESIDESINTHEAGLYCONE,WHEREASTHESUGARRESIDUESAFFECTTHESOLUBILITYANDPOTENCYOFTHEDRUGTHEAGLYCONEISS

13、TRUCTURALLYRELATEDTOBILEACIDS,STEROLS,SEXHORMONESANDADRENOCORTICALHORMONESDTUBOCURARINEANDITSDERIVATIVESARETHEMOSTFREQUENTLYUSEDDRUGSINOPERATINGROOMSTOPROVIDEMUSCLERELAXATIONANDPREVENTMUSCLESPASMTHESEAGENTSINTERRUPTTHETRANSMISSIONOFTHENERVEIMPULSEATTHESKELETALNEUROMUSCULARJUNCTIONCURARE,THECOMMONNAM

14、EFORSOUTHAMERICANARROWPOISONS,HASALONGANDINTERESTINGHISTORYITHASBEENUSEDFORCENTURIESBYINDIANSALONGTHEAMAZONANDORINOCORIVERSFORHUNTINGITCAUSESPARALYSISOFTHESKELETALMUSCLESOFANIMALSANDFINALLYRESULTSINDEATHTHEMETHODSOFCURAREPREPARATIONWEREASECRETENTRUSTEDONLYTOTRIBALDOCTORSSOONAFTERTHEIRDISCOVERYOFTHEA

15、MERICANCONTINENT,EUROPEANEXPLORERSBECAMEINTERESTEDINCURAREINTHELATE16THCENTURY,SAMPLESOFNATIVEPREPARATIONSWEREBROUGHTTOEUROPEFORINVESTIGATIONCURARE,ANALKALOID,WASFOUNDINVARIOUSSPECIESOFSTRYCHNOSANDCERTAINSPECIESOFCHONDRODENDRONTHEFIRSTUSEOFCURAREFORMUSCLERELAXATIONWASREPORTEDIN1942BYGRIFFITHANDJOHNS

16、ONTHISDRUGOFFERSOPTIMALMUSCULARRELAXATIONWITHOUTTHEUSEOFHIGHDOSESOFANAESTHETICSITTHUSEMERGEDASTHECHIEFDRUGFORUSEINTRACHEALINTUBATIONANDDURINGSURGERYVINBLASTINEANDVINCRISTINEARETWOOFTHEMOSTPOTENTANTITUMOURDRUGSTHEYAREOBTAINEDFROMCATHARANTHUSROSEUS,COMMONLYKNOWNASTHEROSYPERIWINKLETHISPLANT,INDIGENOUST

17、OMADAGASCAR,ISALSOCULTIVATEDININDIA,ISRAELANDTHEUSITWASORIGINALLYEXAMINEDFORCLINICALUSEBECAUSEOFITSTRADITIONALUSEINTREATINGDIABETESTHELEAVESANDROOTSOFTHISPLANTCONTAINMORETHAN100ALKALOIDSFRACTIONATIONOFTHESEEXTRACTSYIELDSFOURACTIVEALKALOIDSVINBLASTINE,VINCRISTINE,VINLEUROSINEANDVINRESIDINETHESEALKALO

18、IDSAREASYMMETRICDIMERICCOMPOUNDSREFERREDTOASVINCAALKALOIDS,BUTOFTHESE,ONLYVINBLASTINEANDVINCRISTINEARECLINICALLYIMPORTANTANTITUMOURAGENTSTHESETWOALKALOIDSARECELLCYCLESPECIFICAGENTSTHATBLOCKMITOSISCELLDIVISIONVINCRISTINESULPHATEISUSEDTOTREATACUTELEUKAEMIAINCHILDRENANDLYMPHOCYTICLEUKAEMIAITISALSOEFFEC

19、TIVEAGAINSTWILMSTUMOUR,NEUROBLASTOMA,RHABDOMYOSARCOMATUMOUROFVOLUNTARYORSTRIPEDMUSCLECELLS,RETICULUMCELLSARCOMAANDHODGKINSDISEASEVINBLASTINESULPHATEISUSEDINTHETREATMENTOFHODGKINSDISEASE,LYMPHOSARCOMA,CHORIOCARCINOMA,NEUROBLASTOMA,CARCINOMAOFBREAST,LUNGANDOTHERORGANS,ANDINACUTEANDCHRONICLEUKAEMIAEMER

20、GINGPLANTMEDICINESARTEMISININISTHEMOSTRECENTANTIMALARIADRUGDEVELOPEDFROMPLANTBASEDTRADITIONALMEDICINEITISISOLATEDFROMTHELEAVESANDFLOWERSOFARTEMISIAANNUALCOMPOSITAE,COMMONLYKNOWNASTHESWEETWORMWOOD,ACOUSINOFTARRAGONINDIGENOUSTOCHINA,THEEXTRACTOFTHISPLANTISTRADITIONALLYKNOWNASTHEQINGHAOITHASBEENUSEDTOT

21、REATMALARIAINCHINAFOROVER2000YEARSITSACTIVECOMPONENT,ARTEMISININ,WASFIRSTISOLATEDINTHE1970SBYCHINESESCIENTISTSUNLIKEQUININEANDCHLOROQUINE,THISCOMPOUNDISNONTOXICRAPIDINEFFECT,ANDSAFEFORPREGNANTWOMENFURTHERMORE,ITISEFFECTIVEAGAINSTCHLOROQUINERESISTANTPLASMODIUMFALCIPARUMMALARIAANDINPATIENTSWITHCEREBRA

22、LMALARIAITKILLSTHEPARASITESDIRECTLYSOPARASITEMIAISQUICKLYCONTROLLEDTHISWORKWASCONFIRMEDBYTHEWHOINAFRICAANDOTHERPARTSOFSOUTHEASTASIAARTEMISININISANENDOPEROXIDEOFTHESESQUITERPENELACTONETHESTRUCTUREOFTHISCOMPOUNDISTOOCOMPLEXTOBESYNTHESISEDEFFECTIVELYARTEMISIAISALSOFOUNDINMANYPARTSOFTHEUS,ABUNDANTLYALON

23、GTHEPOTOMACRIVERINWASHINGTONDC,BUTTHEDRUGCONTENTOFTHESEVARIETIESISONLYABOUTHALFTHATOFTHECHINESEVARIETYCURRENTLY,THEWHOANDTHEUSAREJOINTLYENGAGEDINTHECULTIVATIONOFCHINESEARTEMISIAFORWORLDWIDEUSETHISRECENTDEVELOPMENTOFFERSRENEWEDHOPEFORUSINGTRADITIONALMEDICINETOPROVIDENEWDRUGSFORFUTUREMEDICINES1PRESCRI

24、PTIONN处方,药方,规定2WORLDHEALTHORGANIZATION世界卫生组织缩写为WHO3ADRENERGICA肾上腺素的,类似肾上腺素的,释放肾上腺素的4ARTEMISININ青蒿素5ANTIMALARIAN抗疟疾,防疟疾6FRACTIONATIONN分馏7COUNTERPARTN配对物,副本,极相似的人或物8RESURGENTA复活的,苏醒的,恢复活力的9ASTHMAN哮喘10ADRENALN肾上腺A肾上腺的11GLANDN腺12PHARMACOLOGICALLYAD药理地,药学地,药用地13PRESSORN升高血压的物质A有使血压增高的,收缩血管的14HYPOTENSIONN

25、低血压15ANAESTHESIAN麻醉法,感觉缺乏,麻木16NASALA鼻的,护鼻的,鼻音的N鼻音,鼻音宇17ENDOGENOUSA内生的,内长的18NORADRENALINENNOREPINEPHRINE去甲肾上腺素19DIGITALISN洋地黄20ARRHYTHMIAN心律不齐21CONTRACTILITYN收缩性,缩小性,伸缩力22VASCULARA脉管的,血管的,有脉管的23ATRIOVENTRICULARA房室的,心房与心室的24NODEN结25ATRIALA心房的,有关心房的26FIBRILLATIONN纤维性颤动27DIGITALISPURPUREA紫花毛地黄28DIGITALI

26、SLANATA毛花洋地黄29FOXGLOVEN毛地黄30DIURETICN利尿剂A利尿的31AHEARTTONIC强心药32VENOMN毒液33TOADN蟾蜍,癞蛤蟆34CARDIACN强心剂,强胃剂A心脏的,胃的贲门的35BOTANICALLYAD植物学地36GLYCOSIDEN苷,配糖类,配糖物37AGLYCONEN配质,配基,苷的非糖部38GENINN配质,配基39SOLUBILITYN溶解度,溶解性,可溶性40POTENCYN效力,效验,能力,潜力,力量41BILEACID胆汁酸42STEROLN甾醇,固醇43SEXHORMONE性激素44ADRENOCORTICALHORMONEN肾

27、上腺皮质激素45DIGOXIGENINN异羟基洋地黄毒苷,地谷新配质46DIGITOXIGENINN毛地黄毒苷配基,户丁烯酸内酯14羟甾醇47DTUBOCURARINEND管箭毒碱48RELAXATIONN松弛,缓和,减轻,放宽49SPASMN痉挛,一阵发作50SKELETALA骨骼的,骸骨的51NEUROMUSCULARA神经肌肉的52CURAREN箭毒,马钱子属植物,马钱子也叫番木鳖53PARALYSISN瘫痪,麻痹54ENTRUSTEDVT委托,托管,信托55STRYCHNOSNS马钱子属,毒鼠碱56CHONDRODENDRONN南美防己属57TRACHEALA气管的,导管的,呼吸管的5

28、8INTUBATIONN插管,插管法59VINBLASTINEN长春碱60VINCRISTINEN长春新碱61ANTITUMOURN抗癌的,抗肿瘤的62CATHARANTHUSROSEUS长春花63PERIWINKLEN长春花属的植物,玉黍螺64INDIGENOUSA本土的65MADAGASCARN马达加斯加岛非洲岛国66DIABETESN糖尿病,多尿症67VINLEUROSINEN环氧长春碱68VINRESIDINENLEUROSIDINE异长春碱,洛诺西丁69ASYMMETRICA不对称的,不均匀的70DIMERICA二聚的,形成二聚物的71VINCAN长春花72VINCRISTINESU

29、LPHATE硫酸长春新碱73ACUTEA急性的,敏锐的74CHRONICA慢性的,延续很长的75LEUKAEMIAN白血病76LYMPHOCYTICA淋巴球的,淋巴细胞的77NEUROBLASTOMAN成神经细胞瘤78RHABDOMYOSARCOMAN横纹肌肉瘤79STRIPEDN有斑纹的80SARCOMAN肉瘤,恶性毒瘤81LYMPHOSARCOMAN淋巴肉瘤82CHORIOCARCINOMAN绒膜癌83CARCINOMA复CARCINOMAS或CARCINOMATAN癌84ANTIMALARIAN抗疟疾85ARTEMISIAANNUAL黄花蒿屑植物,青蒿属植物86COMPOSITAEN菊科

30、87WORMWOODN蒿属植物88TARRAGONN龙蒿,龙蒿叶89MALARIAN疟疾,瘴气90QUININEN奎宁91CHLOROQUINEN氯喹92PLASMODIUMFALCIPARUM恶性疟原虫,镰状疟原虫93CEREBRALA脑的,大脑的94PARASITEN寄生虫,食客95PARASITEMIAN寄生虫血症96ENDOPEROXIDEN桥过氧化物97SESQUITERPENEN倍半萜烯98LACTONEN内酯THEAUTONOMICANDCENTRALNERVOUSSYSTEMSALLCHEMICALSUBSTANCESTHATHAVEAPOTENTIALFORABUSEPROD

31、UCETHEIRDESIRABLEANDOFTENUNDESIRABLEEFFECTSBYMECHANISMSINVOLVINGTHENERVOUSSYSTEMTOUNDERSTANDHOWABUSEDSUBSTANCESPRODUCETHEIRSOUGHTAFTEREFFECTSANDWHYVARIOUSMODALITIESAREUSEDTOTREATTHEIRTOXICMANIFESTATIONS,ABASICKNOWLEDGEOFTHESTRUCTUREANDFUNCTIONOFTHENERVOUSSYSTEMISNECESSARYTHEFOLLOWINGOVERVIEWPRESENTS

32、THEMAJORCOMPONENTSOFTHENERVOUSSYSTEMANDTHEIRFUNCTIONSTHISINFORMATIONISNOTINTENDEDASACOMPREHENSIVEREVIEWOFNEUROANATOMY,BUTRATHERASABASISFORUNDERSTANDINGTHEDRUGRELATEDMATERIALTOBEPRESENTEDINLATERCHAPTERSINTHISTEXTADDITIONALINFORMATIONMAYBEOBTAINEDFROMTHEREFERENCESANDSELECTEDREADINGSLISTEDATTHEENDOFTHI

33、SCHAPTERANATOMICALLY,THENERVOUSSYSTEMISDIVIDEDINTOTWOMAJORCOMPONENTSTHECENTRALNERVOUSSYSTEMCNSANDTHEPERIPHERALNERVOUSSYSTEMTHECNS,COMPOSEDOFTHEBRAINANDSPINALCORD,ISRESPONSIBLEFORINTEGRATIVEFUNCTIONSRELATEDTOBOTHCONSCIOUSANDSUBCONSCIOUSACTIVITIESOFTHEBODYITISALSOULTIMATELYRESPONSIBLEFORTHEINTERPRETAT

34、IONOF,ANDREACTIONTO,ALLINFORMATIONTHATTHEBODYRECEIVESFROMTHEENVIRONMENTTHEPERIPHERALNERVOUSSYSTEMISMADEUPOFNERVEFIBERSTHATCONDUCTINFORMATIONTOWARDTHECNSAFFERENTFIBERSANDNERVEFIBERSTHATCONDUCTDIRECTIVESFROMTHECNSTOALLBODYAREASEFFERENTFIBERSBEFOREUNDERTAKINGAGENERALDISCUSSIONOFTHENERVOUSSYSTEM,ABRIEFR

35、EVIEWOFTHEBASICUNITOFTHENERVOUSSYSTEM,THENEURON,ANDTHEMECHANISMSBYWHICHINFORMATIONISTRANSFERREDTHROUGHOUTTHENERVOUSSYSTEMISINORDERTHENEURONTHENEURON,ORNERVECELL,ISTHEBASEOFALLACTIVITIESOFTHENERVOUSSYSTEMNEURONSDIFFERFROMOTHERBODYCELLSINTWORESPECTS1THEYCANCONDUCTINFORMATIONINTHEFORMOFELECTRICALIMPULS

36、ESOVERLONGDISTANCESAND2THEYRELATETOOTHERNERVECELLSANDINNERVATEDTISSUEINAHIGHLYSPECIALIZEDMANNERTHENEURONCONSISTSOFACELLBODY,ANAXON,WHICHCARRIESINFORMATIONAWAYFROMTHECELLBODY,ANDONEORMOREDENDRITES,WHICHCARRYINFORMATIONTOWARDTHECELLBODYSOMEAXONSARESURROUNDEDBYALAYEROFFATTYTISSUECALLEDAMYELINSHEATH,WHI

37、CHDEVELOPSWITHINTHENERVOUSSYSTEMOVERAPERIODOFYEARSANDSERVESASAPROTECTIVECOATINGTHEABILITYOFTHENEURONTOTRANSMITINFORMATIONFROMONESITETOANOTHERISAFUNCTIONOFITSELECTRICALTRANSMISSIONCAPABILITYANDITSCAPACITYTOSYNTHESIZE,STORE,ANDRELEASEHIGHLYSPECIFICCHEMICALSNEUROTRANSMITTERSFROMNERVEENDINGSTHESITEWHERE

38、TWONERVEENDINGSMEETORWHEREANERVEMEETSTHETISSUETHATITINNERVATESISASMALLGAPTHATISTERMEDTHESYNAPSE,ORSYNAPTICCLEFTINORDERFORELECTRICALIMPULSESTOCROSSASYNAPSE,ANEUROTRANSMITTERISRELEASEDFROMONENERVEENDINGTOTRAVELACROSSTHESYNAPSEANDSTIMULATERECEPTORSONANADJACENTNERVEORTISSUETHEPERIPHERALNERVOUSSYSTEMTHEP

39、ERIPHERALNERVOUSSYSTEMCONSISTSOFALLTHENERVEFIBERSTHATCONDUCTINFORMATIONTOANDFROMTHECNSANDTHATLIEOUTSIDETHEBRAINANDSPINALCORDPERIPHERALAFFERENTFIBERSAREINVOLVEDWITHSENSATIONSSUCHASPAIN,TEMPERATURE,ANDTOUCH,WHEREASPERIPHERALEFFERENTFIBERSAREINVOLVEDWITHTHECONTROLOFSPECIFICBODYFUNCTIONSEFFERENTFIBERSAR

40、EDIVIDEDINTOTWOCATEGORIES1SOMATICFIBERS,WHICHCONTROLTHEFUNCTIONOFSKELETALMUSCLE,AND2AUTONOMICFIBERS,WHICHCONTROLTHEACTIVITIESOFSMOOTHMUSCLE,CARDIACMUSCLE,ANDGLANDSOFEXCRETIONSOMATICNERVEFIBERSLEAVETHESPINALCORDATVARIOUSLEVELS,DEPENDINGONTHELOCATIONOFTHEINNERVATEDSKELETALMUSCLE,ANDCONTINUEASANUNINTER

41、RUPTEDUNITFROMTHEIRSITEOFORIGINMOTORNEURONTOSKELETALMUSCLETISSUETHESITEATWHICHTHESOMATICFIBERMEETSTHESKELETALMUSCLEISTERMEDTHENEUROMUSCULARJUNCTIONNMJTHENEUROTRANSMITTERATTHENMJISACETYLCHOLINEAUTONOMICEFFERENTFIBERSCONTROLTHEAUTOMATICORSUBCONSCIOUSFUNCTIONINGOFSMOOTHANDCARDIACMUSCLEANDEXOCRINEGLANDS

42、THESEFIBERSARERESPONSIBLEFORACTIVITIESSUCHASTHEMAINTENANCEOFTONEINTHEGASTROINTESITINALTRACTANDBLOODVESSELS,REGULATIONOFHEARTRATEANDRELEASEOFSUBSTANCESSUCHASSALIVA,RESPIRATORYSECRETIONS,ANDGASTRICACIDAUTONOMICFIBERTRACTSACTUALLYCONSISTOFTWOSEPARATEFIBERSTHEFIRSTFIBERPRESYNAPTICFIBERORIGINATESINSIDETH

43、ESPINALCORDANDTERMINATESATASYNAPSESOMEWHEREINTHEPERIPHERYTHESECONDFIBERPOSTSYNAPTICFIBERORIGINATESATTHESYNAPSEANDTERMINATESATTHEINNERVATEDTISSUEINMOSTINSTANCES,THESYNAPSESOFANUMBEROFFIBERSAREGROUPEDTOGETHERANDTERMEDAGANGLIONINSUCHCASES,THEPRESYNAPTICANDPOSTSYNAPTICFIBERSAREREFERREDTOASPREGANGLIONICA

44、NDPOSTGLANGLIONICFIBERS,RESPECTIVELYTHESITEATWHICHTHEPOSTGANGLIONICFIBERSYNAPSESWITHTHEINNERVATEDTISSUEISTERMEDTHENEUROEFFECTORJUNCTIONNEJAUTONOMICFIBERSARECATEGORIZEDBYTWOMETHODSTHEFIRSTANDOLDERMETHODOFCLASSIFICATIONISBASEDONTHESITESATWHICHPREGANGLIONICFIBERSLEAVETHECNSNERVESTHATEXITFROMTHETHORACIC

45、ANDLUMBARLEVELSOFTHESPINALCORDARETERMEDSYMPATHETIC,WHEREASTHOSETHATEXITFROMTHESACRALLEVELOFTHESPINALCORDANDCRANIUMARETERMEDPARASYMPATHETICTHESECONDMETHODOFCLASSIFICATIONISBASEDONTHENEUROTRANSMITTERRELEASEDATTHENEJBYTHENERVEFIBERNERVESTHATRELEASEACETYLCHOLINEACHARETERMEDCHOLINERGIC,WHEREASTHOSETHATRE

46、LEASENOREPINEPHRINENEARETERMEDADRENERGICINGENERAL,THETERMSYMPATHETICISINTERCHANGEABLEWITHADRENERGICANDTHETERMPARASYMPATHETICISINTERCHANGEABLEWITHCHOLINERGICCHOLINERGICANDADRENERGICAREUSUALLYTHEPREFERREDTERMSWHENDISCUSSINGDRUGEFFECTSONAUTONOMICFUNCTIONBECAUSETHEYDESIGNATETHESPECIFICNEUROTRANSMITTERSA

47、FFECTEDBYTHEDRUGSWITHINTHEAUTONOMICNERVOUSSYSTEMANS,RECEPTORSITESFORACHANDNEHAVEAVERYSPECIFICNOMENCLATUREBASEDUPONTHEIRLOCATIONANDFUNCTIONCHOLINERGICRECEPTORSITESAREFOUNDINTHEGANGLIONICSYNAPSESOFBOTHTHESYMPATHETICANDPARASYMPATHETICNERVOUSSYSTEMTHEYAREALSOFOUNDATTHENEJOFPARASYMPATHETICFIBERSCHOLINERG

48、ICRECEPTORSITESARECATEGORIZEDASBEINGEITHERMUSCARINICORNICOTINIC,BASEDONWHETHERTHEYRESPONDTOTHEALKALOIDSMUSCARINEORNICOTINE,RESPECTIVELYMUSCARINICRECEPTORSAREFOUNDATTHEPARASYMPATHETICNEJNICOTINICRECEPTORSAREFOUNDATALLAUTONOMICGANGLIAANDATTHESOMATICNMJADRENERGICRECEPTORSITESINTHEANSAREFOUNDONLYATTHESY

49、MPATHETICNEJADRENERGICRECEPTORSAREDIVIDEDINTOTHREECATEGORIESALPHA,BETA1,ANDBETA2INGENERAL,STIMULATIONOFTHEALPHAADRENERGICRECEPTORSITECAUSESANINCREASEINACTIVITYOFTHEINNERVATEDTISSUEALPHARECEPTORSAREFOUNDPRIMARILYINARTERIOLESANDTHEREFOREAREIMPORTANTINTHEMAINTENANCEOFBLOODPRESSURESTIMULATIONOFALPHARECEPTORSBYNELEADSTOARTERIOLARCONSTRICTION,WHICHINCREASESBLOODPRESSUREBETA1RECEPTORSAREFOUNDONLYINCARDIACTISSUESTIMULATIONOFTHESERECEPTORSLEA

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