沈阳药科大学博士学位论文摘要 过^C—cAMP—PKA途径而显著扩张气道平滑肌,稳定肥大细胞,增强气道纤毛运动 能力,从而发挥抗哮喘作用。由于结构的关系,该药物的作用时间也较长。本药 物还因受体选择性较高而较少引发相关的副作用,因而安全性较高。但由于SPFF 仍然具有导致受体脱敏的可能性,因此本化合物不宜长期单独使用。本研究为SPFF 的迸一步开发提供了一定的药理学依据。 关键词:SPFF,2-(4一氨基一3一氯一5一三氟甲基苯基)一2一(叔丁氨基)一乙醇盐酸盐 13z肾上腺素受体激动剂,气道扩张,哮喘, 作用机制,初步安全评价 APHAMACOLOGICALSTUDYONTHEANTI-ASTHMAEFFECTSOF SPFF,A NOVEL pz ADRENOCEPTORAGONIST ABSTRCT SPFF,[2-(4-Amino 3-chloro-5一trifluomethyl—phenyl)一2-tert.-butylamino ethanol chloride],was newlysynthesized13 adrenergicagonistbyUS.Inthis paper,we examinedthe bronchodilatingeffects,thereceptorological characteristics andthe actionmechanismofthis compound.And safetyevaluationworkwasalso carriedout. Westudiedinvitrothe bronchodilating effectsofSPFFand isoprenaline(I￥O)on isolated guinea pig trachea strips isoprenalinedose-dependentlydecreased restingtensionofisolated guineapig trachea strips pD2valuesof7.66+0.68 8.79土0.19。respectively.SPFFalso dose—dependently relaxedtheisolated guinea pig trachea stripprecontraction withHisorAch.andthemaximuminhibitionrateof theeffectswas146%and 82.6%,respectively.Moreover,we confirmedthatthe bronchodilatoreffectofSPFFwasduetotheactivationofB2 adrenoceptor because effectwaseasily antagonizedbyICI 118551(pA28.90+0.01),a specific 13 adrenoceptorantagonist.Inaddition.SPFF(3xlO~,3x10一reel,L。1)significantlyinhibitedthebronchoconstrictioneffectofhistamineinisolated lungperfusion model guineapigs.The protective effects SABonbronchospasm induced bronchoconstrictoraerosolinguineapigs invivowere investigated.and theKonzett andRfssler experiment inrabbitsinvivowasalso performed.The resultsshowedthat SPFF significantlyprolonged latencytimeofhistamineand acetylcholine induced asphyxiationcollapse guineapigs:theEDsovalueofSPFF i.g.was O.32+0.05 mg/kg -4. inthisexperiment.Meanwhile,the ED50valuesofSABwas2.37O.22,which meant thatthebronchorelaxationeffectofsalbutamolwasabout8timesless potent thanthat ofSPFFin vivo.TheresultoftheKonzettandR6ssler experimentperformed anesthetizedrabbitsshowedthatintraduodenaladministrationofSPFFexertedan action longerduration than salbutam01.SPFF(i.d)20、40、80j-tg/kg also significantlyimproved thealterationof lungcompliance andresistanceinduced Hisaerosolinanesthetizedrabbits.Fromtheresultsabovewe suggested thatSPFFwasa potent,long-acting bronchodilatorwith relativelyhigherB2adrenoceptorselectivity. Moreover,SPFF(3x10一.3x10~m01.L。1)inhibited ovalbumin—allergicrats lungfragments,which indicatedamastcell protection effectof investigationoftheeffectofSPFFonthemucus movement,it wasshownthatSPFF i.g 0.04、0.1、O.25 mg/kgimproved thecilium transportation functiononthetracheaofconscious pigeon whilehadnoeffectontheair way mucus excretionin mice,these results impliedthat,byprompting theclearanceof airway, SPFFhada11additionalbeneficialeffectonthealleviationofasthma symptom. The positivechronotropic effectsofSPFFinisolated guineapig left atria(pD2, 5.41+0.38)was2200timesless potent thanthatof ISO,and 132ARselectivityindex(109’。[pD2(trachea)-pD2(atria)】)obtained fromfunction experiments was178 1,respectively,forSPFFand ISO.Meanwhile,theselectivity indexobtainedfrom radio-ligandcompetitiveassayusing 3H—DHAforSPFFandISOwas4.6 and0.36. respectively.This resultindicatedthatSPFFhada higheraffinity 132ARthanISO. AsSPFF i.g(O.25、0.5、lmg/kg)dramatically elevatedthecAMPlevelinthe lung tissuein rat,andsignificantly decreasedtheCa2+levelin primary culturesof guinea pig tracheasmoothmuscle cells,we confirmedthatthe signal transduction pathway SPFFshouldalsobeproteinG-cAMP-Ca”,which wasthesameasother B2 agonists. ThedesensitizationcharacteristicofSPFFwasstudiedinvitroandinvivo.In isolated guineapig trachea strips,when incubated SABorSPFF concentrationof1xl0~t001.L~for1h,severetachyphylaxis wasinduced bySAB, meanwhile,SPFF didnotinduced tachyphylaxis inthis model.However,whengiyen -5. 沈阳药科大学博士学位论文 ABSTRACT i.g(O.2mg/kg)for18 elevationeffectofSPFFoncAMPlevelwasnotgained asthmaticrats,andthedecreasein BmaxandKd valuesin radioligandassay performed inasthmaticrat lung membrane indicating thatthenumberandthestructure 132ARwerealtered SPFFadministration.ItmeantthaiSPFF,like other p2 agonists,when administeredalonein highdose,would result insevere receptor desansitivity. Thedataofthe safety evaluationofSPFFshowedthat SPFF(5,50,500扯g/kgi名) didnotinduce any sideeffectsincardiovascularand respiratorysystem inanesthetized cats;additionally,thedepression effectonthenervous system(2,20,200rtg/kg,i.g)in mice,ifany,was ratherweak.The onlydrug—related sideeffectobservedinour study wasskeletalmuscletremor.Intheacute toxicity studies,theLDs0 values(95% confidential limits)of SPFFwas 378.5(331.8-425.2,i.g)mg/kg,which was60,000 times higher thanhumanclinicalrecommendation dose.Moreover,the resultsofthe mutagenicitytests(Amestest,micronueleusassay andchromosomalaberration test) indicatedthatSPFFwasnot mutagenic overthedose range tested. In conclusion,SPFF wasa highly selective B2ARagonist.By theactivationof 132AR,SPFF inducedtherelaxationoftracheasmooth muscle,thestabilizationof lung mastcells andthe improvement ofthe cilium transportation function,therefore eventually resultedinthealleviationoftheasthmatic symptom.Due toits unique chemical structure,SPFF alsohada longer actiondurationthan commonlyused2 agonists suchas SAB,and highp2ARselectivityensuredalowerclinical side effectincidenceofthis compound.As itspotential p2ARdesensitization,werecommendedthatin long term administration,SPFF shouldnotbeusedalone. This research providepowerful pharmacological basis developingSPFFasananti asthma agent. KEY WORDS:SPFF,2-(4一amino一3-chloro-5-trifluomethyl—phonyl).2-tort -butylamino。