支气管扩张剂作用的分子药理机制

1、支气管扩张剂作用的分子药理机制,上海市瑞金医院,黄绍光,Epidemiology / pathology,Control of airway diameter,?,自主神经参与调节许多气道功能，影,响气道平滑肌，粘液分泌，血管、微,血管通透性，炎症细胞的迁移和释放。,神经机制在气道炎症疾病中可放大或,调节炎症反应，其中胆碱能神经是引,起气道收缩的主要因素。,Increased maximal airway narrowing,in asthma,Thickening and increased stiffness,Inner airway wall,Hypertrophy and increa

2、sed contractility,Airway smooth muscle,Loss of elastio parenchymal recoil,Airway pathology in COPD,Normal,COPD,Disrupted alveolar,attachments,(emphysema),Mucosal,inflammation,and fibrosis,Mucus,hypersecretion,Airway held open by,alveolar atteachments,?,Airway obstructed by,?,lossof attachments,Mucos

3、al inflammationand fibrosis,?,Mucus obstruction of lumen,三大类支气管扩张剂作用机制,抗胆碱能药物,M1,M2,M3,cGMP,收缩,cAMP,舒张,AMP,平滑肌细胞,?,2,-,受体激动剂,茶碱,?,肾上腺素能受体激动剂做为最主要,的支气管扩张剂在支气管哮喘及慢性,阻塞性肺病（,COPD,）等慢性气道疾,病的治疗中得到了广泛的应用。,b,2,-Agonists,-,Smooth muscle,Histamine,LTD,4,Acetylcholine,Cholinergic,nerve,Eosinophil,?,Mast cell,-

4、,-,b,2,-Agonists,-,?,所有,受体激动剂都是,苯乙胺的衍生物,，其儿,茶酚环上的羟基位置与作用持续时间相关，改,变羟基位置，如间羟异丙肾上腺素、或加上其,他基团作为替代物，如沙丁胺醇（配基糖苷,类），可防止儿茶酚氧甲基转移酶,（,COMT,）的代谢；而,N,端的结构则关系到作,用的选择性，其取代基越大对,受体的选择性,就越强，而,受体的活性就下降（如异丙肾上,腺素），还可促进对单胺氧化酶（,MAO,）的,抵抗，进一步增加,N,端的结构则对,2,受体的选,择性更强。,b,受体激动剂的母核,CH,b,CH,a,NH,苯乙胺核,b,2,-agonists,化学结构,H,O,CH,2

5、,H,O,OH,CHCH,2,NH,O,CH,3,H,N,H,H,O,OH,CH,3,CH,3,CH,3,O,CH,3,CHCH,2,NHCHC,H,2,Salbutamol: short side chain,Formoterol: medium side chain,H,O,CH,2,H,O,OH,CHCH,2,NH,CH,2,CH,2,CH,2,CH,2,CH,2,CH,2,O,CH,2,CH,2,CH,2,CH,2,Salmeterol: long side chain,人类,b,2,肾上腺受体的分子结构,糖基化,NH,2,EL1,2,3,细胞外,细胞膜,VI,3,VII,4,TMD,

6、I,胞浆,IL1,II,III,2,IV,V,棕榈酰化榈,413,氨基酸,b,2,激动剂结合点,COOH,?,受体是通过细胞内腺苷酸环化酶增加而,介导其活化过程。,受体的信号转导系统,是核苷酸调节蛋白,Gs,，,受体和腺苷酸环,化酶的偶联是通过三维体,Gs,蛋白，包括,、,、,亚单位，,G,蛋白可以兴奋（,Gs,）或,抑制（,Gi,）腺苷酸环化酶，因此可以增,加或减少细胞,cAMP,的浓度。,b,2,激动剂激动,b,2,受体,(,b,2,AR),程序图,b,2,-Agonist,b,2,AR,K,+,Blocked by,CHARYBDOTOXIN,Cell,membrane,AC,a,s,G

7、,S,a,s,G,S,Ca,2+,-activated K,+,channel activation,PI hydrolysis,Na,+,/Ca,2+,exchange,Na,+,/K,+,ATPase,MLCK,ATP,Cyclic 35AMP,PKG,PKA,G,S,：兴奋型,G,鸟核苷酸结合蛋白（,Gs,）,；,AC,：腺苷酸环化酸；,PKA,：蛋白激酶,A,PI,：磷酸肌醇；,MLCK,：肌凝蛋白轻链激酶,Barnes PJ AJRCCM 1995,微动力弥散理论,Aqueous biophase,Cell membrane,with ?,2,-receptor,Salbutamol

8、,Hydrophilic,Short duration,Fast onset,Formoterol,Intermediate,Long duration,Fast onset,Salmeterol,Lipophilic,Long duration,Slow onset,Anderson,.,Life Sci 1993,微动力学,福莫特罗,中度亲脂性,长作用,起效快,微动力学,沙美特罗,亲脂性,长作用,起效慢,油,/,水,23000/1,膜吸收,(1,分钟,),慢吸入,(,?,25,分钟,),如穿透上皮、支气管腔、平滑肌靶,ASP 113,Active,site,SER 205,SER 207,

9、Exo-,site,a,G-Protein,b,g,The exosite binding hypothesis,-,O,-,CH,2,-,CH,2,-,CH,2,-,CH,2,Active site,Exo-site,?,2,-receptor,Johnson, Med Res Rev, 1995,Classes of,b,2,-agonists,Speed of,onset,RESCUE MEDICATION,fast onset, long duration,fast onset, short duration,fast,inhaled terbutaline,inhaled salbu

10、tamol,slow onset, short duration,inhaled formoterol,slow onset, long duration,inhaled salmeterol,oral bambuterol,Duration,of action,slow,oral terbutaline,oral salbutamol,oral formoterol,M,A,I,N,T,E,N,A,N,C,E,short,long,福莫特罗,是,沙美特罗,是,b,2,受体完全激动剂,(full,agonist),b,2,受体部分激动剂,(partial,agonist),部分激动剂是指药物与

11、受体结合后只可激发,较弱的生理效应，即内在活性,(intrinsic activity),小，但它同时却都妨碍其他激动药与此受体结合,和激发效应。,Mechanism of action of,b,2,-agonists,Bronchodilatation,b,2,-agonists,?,Plasma,exudation,?,Bacterial,adherence,?,Cholinergic,neurotransmission,?,Mucociliary,clearance,?,Neutrophil,function,MAST CELL,b,2,-DRENOCEPTIORS,Histamine

12、,Methacholine,Allergen,Adenosine,Direct,Histamine,LTD,4,Airway,Smooth muscle,Indirect,Mast cell,b,2,-Agonists,AMPmethachaline/histamine protection =,Mast cell stabilising effect,EFFECT OF INHALED,b,2,-AGONWISTS ON,PLASMA EXUDATION IN AIRWAYS,Guinea pig trachea,70,60,50,control,Formoterol,Salbutamol,

13、Histamine,b,2,-Agonist,?,40,30,20,10,0,Plasma exudation,EFFECT OF FORMOTEROL ON AIRWAY,SENSORY NERVES,Guines pig bronchiinvitro,EFS: 40v, 0.5ms,6Hz,C,o,n,t,r,a,c,t,i,o,n,(,%,c,o,n,t,r,o,l,),100,80,60,40,20,0,SP,SP,SP,SP,Sensory,nerve,b,2,-receptor,e-NANC,Formoterol,Ptopranolol,5P,Venceen G et al: J

14、Appl Physiol 1992,Smooth,减敏机制,包括三个主要过程：,1.,受体从,腺苷酸环化酶上解偶联；,2.,解偶联的受体从细胞膜上内,陷；,3.,内陷后的受体磷酸化。,NH2,b,2,-Agonist,Cell membrane,P,a,s,P,cAMP,PKA,PKC,PTK,P,P,B Arrestin,P,P,b,受体磷酸化，导致受体功能缺失。,磷酸化过程中，通过,b,2,受体特异激酶活化，使受体与,G,蛋白介偶,联,该,过,程,涉,及,CAMP,依赖蛋白激酶,A(PKA),b,肾上腺素受体激酶,(,b,ARK),和,其,他,G,蛋,白,受,体,激,酶,(GRK),BAR

15、K,(GRK),细,胞,表,面,受,体,数,目,减,少,(,下,调,现,象,),b,2,-Agonist,受体从细胞膜的内陷，引起细胞表面受,体某种程度的缺失，该过程又称为隔离,UNCOUPLING,DOWN-REGULATION,。,B,g,B,2,B,2,P,P,Cell membrane,AC,ATP,a,s,cAMP,B,2,mRNA STABILITY,cAMP,PKA,TRANSCRIPTION,PKA,CREB,CREB,Nucleus,mRNA,B,2,-Receptor Gene,发生在接触激动剂后数小时,可能是抑制了受体基因的转录或是增加了细胞内,mRNA,转录后的分解代谢

16、,Cholinergic Pathways,Nodose,ganglion,Laryngeal,Esophageal,afferents,CNS,Vagus nerve,Parasympathetic nerve,C fibre,Inflammatory,cell,ACh,Parasympathetic ganglion,ACh,A fibre,C fibre receptors,Irritant receptors,ACh,Submucosal,gland,Airway,epithelium,Airway irritants, mediators,Barnes PJ (1999),节前神经,

17、胆碱能受体,N,副交感神经节,+,M1,+,节后神经,M,2,-,ACH,M,3,+,气道平滑肌,Receptor,M,1,M,2,M,3,Muscarinic Receptors in the Lungs,M,4,M,5,Location in Human Lung,Autonomic ganglia,Submucosal glands,Alveolar walls,Post-ganglionic parasympathetic nerves,Airway smooth muscle,Submucosal glands,Endothelial cells,Not detected,Not d

18、etected,Muscarinic Receptor Subtypes,Parasympathetic,cholinergic nerve,Post-ganglionic,smooth muscle,Airway ganglion,M,1,M,2,M,3,M,1,Agonist,Antagonist,M,2,Pilocarpine,Gallamine,AF-DX 116,Methoctramine,M,3,4-DAMP,HHSiF,McN-A-343,Pirenzepine,Telenzepine,Muscarinic Receptor Subtypes in,Airways,Pre-gan

19、glionic,nerve,Parasympathetic,ganglion,Nicotinic receptors (+),M,1,receptors (+),Post-ganglionic,nerve,M,2,receptors (,),ACh,Airway smooth,muscle,Barnes PJ. Eur Respir Rev (1996),M,3,receptors (+),抗胆碱药物,?,神经机制在气道炎症疾病中可放大或调节炎症反应，,其中胆碱能神经是引起气道收缩的主要因素。它表现,为迷走神经张力增加，乙酰胆碱释放增多，作用气道,平滑肌细胞膜上的,M3,受体，通过偶合,G,蛋

20、白,（,GP/GQ,）使磷脂酶,C,活化，后者促使二磷酸肌醇转,化为三磷酸肌醇，从而使细胞内钙离子释放，导致平,滑肌收缩，乙酰胆碱还作用于,M2,受体，通过耦合抑,制性,G,蛋白（,Gi,），降低腺苷酸环化酶的活性，从而,减少,cAMP,的生成，胆碱能拮抗剂的应用，有其重要,意义。,抗胆碱药物,?,有效的支气管扩张剂,1,2,?,通过抑制胆碱能受体来防止支气管收缩。,?,作用时间长于沙丁胺醇,1,异丙托溴铵,: 4-6,小时,噻托溴铵,: 24,小时,2,适合用于维持治疗,?,和其它支气管扩张剂一起使用，可增加运动量和改善症,状及生活质量,2,3,1. Pauwels et al. 2001,

21、2. Casaburi et al. 2002,3. Vincken et al. 2002,异丙托溴铵,的作用不仅限于解除支气管痉挛,正常,迷走神经,COPD,迷走张力,乙酰胆碱,COPD,没有支气管,痉挛时也可明显,降低气流阻力，,缓解呼吸困难。,COPD,稳定期，胆,碱能张力为气流,阻塞主要可逆因,素。,-,Peter J. Barnes,“,Theoretical aspects,of anticholinergic,treatment,”,抗胆碱能药物,阻力,1/,半径,4,胆碱能阻断剂解除支气管痉挛的机制,调节胆碱能张,力，有效舒张气道。,爱全乐与气道平滑肌,上,M,受体,(,毒蕈

22、碱受,体,),结合，阻断由胆,碱能神经引起的支,气管痉挛,胆碱能阻断剂,支气管痉挛,b,2,受,体,激动剂和,抗胆碱能药物,Infammatory mediator,Acetylcholine,b,2,-agonist,R,G,q,PLC,PKC,P,B,2,G,s,P,AC,IP,3,Dlacylglycerol,Uncoupling,Down-regulation,Ca,2+,Reduced adrenergic,responsiveness,茶碱,?,相对其它支气管扩张剂来说，应用的较少,仅当吸入支气管扩张剂无法使用时才考虑使用缓释茶碱,?,适度的支气管扩张剂,?,在治疗剂量范围内可常见

23、有副作用,治疗指数窄，因此其它支气管扩张剂优先考虑,?,和许多药物有相互作用,?,吸烟能影响茶碱的代谢,Pauwels et al. 2001,?,茶碱的支气管扩张作用是通过抑制磷酸,二酯酶（,PDE,）而产生的，该作用打断,了细胞内核苷的循环途径，从而使细胞,内环磷酸腺苷（,cAMP,）和环磷酸鸟苷,（,cGMP,）的浓度升高。茶碱是一种非选,择性,PDE,抑制剂。,Theophylline as an inhibitor of phosphodiesterases,Agonist,Agonist,Theophylline,Receptor,Inhibition,Phosphodiester

24、ase 3,4,Inhibition,Phosphodiesterase 5,Receptor,Adenylate cyclase,Guanylate cyclase,Adenosine,triphosphate,Cyclic,adenosine,monophosphate,Adenosine,monophosphate,Guanosine,monophosphate,Cyclic,guanosine,monophosphate,Guanosine,triphosphate,Protein kinase A,Protein kinase G,Inflammatory cell inhibiti

25、on,Bronchodilatation,?,腺苷酸受体抑制剂（包括,A1,和,A2,受体,),，这提,示了其支气管扩张作用的基础，,?,增强儿茶酚胺的释放，茶碱可增加肾上腺髓质,分泌肾上腺素,Multiple action of theophylline in asthma,?,Phosphodiesterase,?,Mediators,Bronchodilatation,Mechanism?,Airway smooth muscle,Eosinophil,?,Mediators,?,Numbers,?,Trafficking?,?,Cytokines?,T lymphoctye,Mast

26、cell,?,Leak,?,Migration of,Lymphocytes?,?,Mediators,theophylline,Endothelial cell,Macrophage,?,Neuropeptides,?,Strength,Effects?,Bone marrow,Sensory nerve,Diaphragm,联合治疗,?,联合不同作用机理和持续时间药物进行治疗可以增加支气,管扩张的程度，而副作用相等或更少,1,?,已确定的联合用药,:,短效,b,2,-,受体激动剂,+,短效的抗胆碱剂,?,新的联合用药,:,长效的,b,2,-,受体激动剂,+,吸入激素,1. Pauwels

27、et al. 2001,哮喘炎症过程,急性炎症,急性炎症,激素治疗的,应答状况,慢性炎症,结构改变,时间,Barnes PJ,Effect of wall area on airway resistance during,Airway smooth muscle shortening,Wall area = 20%,30% ASM,shortening,R = 1,R = 7.8,30%,Wall area = 40%,ASM,shortening,R = 1,R = airway resistance,ASM = airway smooth muscle,R = 1.8,R = 80,致,敏

28、,炎,症,症,状,气道高反应性,重,塑,激发因子，气道高反应性及哮喘症状的关系,序贯,激发因子,气道炎症,BHR,分离旁路,激发因子,气道炎症,BHR,症状,激发因子,气道炎症,气道上皮,损伤,平行,激发因子,BHR,可变性气道,堵塞,可变性气道堵塞,可变性气道堵塞,症状,症状,ASTHMA CONTROL,Genes,Atopy,Airway Smooth muscls,Mast cells,Plasma leak,LA,b,2,-Agonists,Environmental,factors,INFLAMMATIONS,CPRTTCDSTERPODS,SYMPTOM,CONTROL,Trea

29、tment of asthma: cellular effects,Virus?,Adenosine,Exercise,Fog,b,2,-Agonists,BRONCHOCONSTRICTION,Mast cell,Macrophage,Airway smooth muscle,Eosinophil,Antigen,Virus?,AIRWAY,HYPERRESPONSIVENESS,T-lymphocyte,Corticosteroids,Cellular effects of glucocorticoids,Eosinophil,Numbers,(apoptosis),Inflammator

30、y cells,Structural cells,Epithelial cell,Cytokines,Mediators,Endothelial cell,Leak,T-lymphocyte,Cytokines,Mast cell,Numbers,Macrophage,Cytokines,Dendritic cell,Numbers,CORTICOSTEROIDS,Airway smooth muscle,2,-Receptors,Cytokines,Mucus gland,Mucus,secretion,Molecular Mechanism of Steroid Action,Cortic

31、osteroid,GR,Lipocortion-1,b,2,-Adrenoceptors,Cytokines,Adhesion,mols,Enzymes,Nucleus,mRNA,hsp90,GR,b,+GRE,-GRE,Steroid-responsive,Target genes,EFFECT OF STEROIDS ON,b,2,-,ADRENOCEPTORS,Corticosteroid,b,2,AR,Glucocortiaid,receptor,Nucleus,mRNA,GRE,GRE,GR,E,b,2,-Receptor gene,激素与,激动剂的协同作用示意图,b,2,-AGON

32、ISTS ACTIVATE GLUCOCORTICOID,RECEPTORS,b,2,-Agonists,?,?,?,?,?,?,A,+ fluticasone,+ dexamothasone,FR,0 0.5 2.5 4 6,0 0.5 2.5 4 6,GR/GRE,complex,Nuclear localisation of,glucocorticoid receptors,Gre binding,Blocked by propranolol,Mimicked by cgclic AMP,expression of a steroid,Inducible gene(P21,(WAF1/CIP1),),B,+ salmeterol,+ salbutamol,unspecific,band,freeprobe,FR,0 0.5 2.5 4 6,0 0.5 2.5 4 6,GR/GRE,complex,unspecific,band,Eickelberg O ct al: J Biol chem 1999,freeprobe,EFFECT PF,b,-AGONIST ON G