A t the end of the 1960s in Great Britain, the

Transcription

1 Development of "Resstance" n Beta Adrenergc Receptors of Asthmatc Patents* Nls L. V. Svedmyr, M.D.; SvenA. Larsson, M.D.; and Gunnar K. Thrnger, M.D. Complete n vtro dose-response curves for '-soproterenol (soprenalne) sulfate showed no functonal defects n bronchal muscular P.adrenergc receptors n three patents wth chromc ntrnsc asthma, as compared to 60 patents wth normal pulmonary functon. Complete ft vvo dose-response curves for ntravenously nfused s0 proterenol were obtaned n eght outpatents wth chronc ntrnsc asthma to regster effects on bronchal muscle (forced expratory volume n one second), heart rate, blood pressure, and skeletal muscular tremor. The s0 proterenol test was performed before and also durng oral treatment wth a long-actng selectve fl-adrenergc stmulator (terbutalne sulfate, 5 mg three tmes daly). The study was performed over 12 months to avod seasonal varaton n basal levels of obstructon and was concluded by addng nhaled terbutalne (two nhalatons four tmes daly) to oral therapy. No "resstance" developed n bronchal p.adrenergc receptors durng ths prolonged tr,,.tment. nhalaton therapy n addton to oral therapy mprovecj bronchoddaton wthout causng resstance. Even sx nhalatons gven four tmes dally (fourto fve-hour ntervals) dd not cause any bronchal resstance; however, resstance developed n skeletal muscles wth decreased tremor and n cardac tj-adrenergc receptors. A t the end of the 1960s n Great Brtan, the publcaton of data suggestng a connecton between the ncrease n acute deaths due to asthma and the sale of,b-adrenergc stmulators n spray form focused attenton on the development of resstance to these drugs. Varous causes for ths connecton have subsequently been proposed. n 1971, Conolly et all suggested development of "resstance" n the,b-adrenergc receptors of bronchal muscles, thus leavng the parasympathetc nervous system and other bronchoconstrctor factors free to take over, whch mght lead to death. t was also suggested that the rsk of developng resstance mght be even greater when longactng selectve {32 adrenergc stmulators were used. Accordng to the theory proposed by Szentvanyf n 1968,,B-adrenergc blockade s the cause of asthma; and pror to any treatment, constrctor mpulses wll produce a pronounced effect and may gve bronchospasm. o From the Clncal Pharmacologcal Laboratory, Unversty Lung Clnc, Benstromska, Hosptal, Coteborg, Sweden. Presented at the X nternatonal Congress on Dseases of the Chest, Amercan College of Chest Physcans, London, July 7-12, Ths nvestgaton was supported by the Swedsh Natonal Assocaton aganst Heart and Chest Dseases and by AB Draco, a subsdary of AB Astra, Sweden. Manuscrpt receved Aprl 2, 1975; revson accepted September 23. Reprnt requests: AB Draco, Eack, S Lund, Sweden Ths theory has receved further support durng recent years, as t has been shown that a certan degree of {3-adrenergc blockade s present n the leukocytes of patents durng acute asthma attacks.v" Snce one of the therapeutc effects of the,b-adrenergc stmulators s nhbtng lberaton of spasmogens from the mast cells, adrenergc blockade could lead to ncreased lberaton of spasmogens. {3-adrenergc blockage n the leukocytes can to some extent be dmnshed by an a-adrenergc blocker and also by cortcosterods," The normalzng effect of a-adrenergc blockers on,b-adrenergc blockade n leukocytes demonstrated by Alston et al" s nterestng n the lght of our prevous fhdngs S,9 that bacteral endotoxn markedly ncreased a-adrenergc receptor-medated bronchospasm n solated bronchal muscles from patents wth arway obstructon. We should, however, dstngush between the 13 adrenergc effect n the bronchal muscle and other,b-adrenergc effects, ncludng that nvolved n lberaton of spasmogens, the clncal sgnfcance of whch s not proved. No studes have been publshed on the functon of the,b-adrenergc receptors n solated bronchal muscles from asthmatc patents. We have, therefore, performed n vtro studes on bronchal muscles from patents wth normal pulmonary functon and CHEST, 69: 4, APRL, 1976 DEVELOPMENT OF "RESSTANCE" N BETA-ADRENERGC RECEPTORS 479

2 from patents wth chronc asthma. Furthermore, for more than one year, we have carred out a study amed at establshng whether resstance really does develop n the,b-adrenergc receptors of the bronch, heart, and skeletal muscles durng treatment wth normal doses of a long-actng,b-adrenergc stmulator n patents wth chronc asthma not prevously treated wth p-adrenergc stmulators. n addton, we performed an overdosage nvestgaton at the end of the study. Prelmnary data from the frst three months of ths study were recently publshed. 1o,11 MATERAL 3.0 FEV, 2B X V 6 4 X 0 The n vtro studes were performed on segmental bronch obtaned from lungs resected for bronchal carcnoma. A total of 67 bronchal muscles from 60 patents wth normal pulmonary functon and sx bronchal-muscle preparatons from three patents wth asthma were used for the n vtro studes. The muscle preparatons were removed n connecton wth surgery for lung cancer but were taken from unnvolved areas of the lung. The n vvo nvestgaton was performed n eght outpatents aged 29 to 66 years; seven were men. The mean body weght was 73 kg (161 lb, range, 58 to 92 kg [128 to 203 b] ). All patents had endogenous asthma of many years' duraton, wth relatvely constant arway obstructon. Some patents also had chronc bronchts. n a prelmnary tral, all patents had been found to have an ncrease of at least 15 percent of ther control value for the forced expratory volume n one second (FEV1.o) after two puffs of -soproterenol (soprenalne) sulfate (160p,g). No patents had sgns of cardac dsease. None was recevng cortsone therapy durng the perod of the study; and wth the excepton of antbotc treatment, none was recevng any therapy other than that gven due to the study. The patents were nfonned of the purpose of the nvestgaton and told that they could demand nterrupton of the study at any phase. The desgn of the study was approved by the ethcal commttee of the Unversty of Coteborg, Sweden. METHODS The n vtro bronchal muscular tests were perfonned as descrbed by Svedmyr et al.12 n the n vvo studes, the patents arrved at the laboratory n the mornng after havng eaten a very lght breakfast. An ntravenous catheter was mmedately nserted nto a cubtal ven, and the patent lay comfortably n a reclnng char throughout the nvestgaton. The basal values for the several varables were determned after 90 mnutes of rest. soproterenol was then nfused ntravenously durng ten-mnute perods n ncreasng doses'at ntervals of 30 mnutes. The lowest dose had a neglgble bronchodlator effect, whle the hghest dose produced almost maxmal bronchodlaton. The followng varables were recorded: FEV1.0, vtal capacty, heart rate determned by contnuous electrocardogram, blood pressure (auscultatory), and skeletal muscular tremor, determned wth an accelerometer attached to the mddle fnger of one hand and usng a carefully standardzed teehnque.p Except for the ECG, whch was recorded contnuously, the varables were recorded durng the last four mnutes of each soproterenol nfuson, when the "steady state" was reached soprenalne sulph. JQ' kg- 1 mn-1 FGURE 1. Effects on ventlaton (FEV1.0) of ncreasng doses of -soproterenol (soprenalne) sulfate nfused ntravenously (soproterenol test) n patents wth chronc asthma not prevously treated wth p-adrenergc stmulatng drugs (thck sold curve) and after 1, 2, 3, 6, 9, and 12 months (,,, V, X, and X) of treatment wth terbutalne sulfate (5 mg three tmes daly per os). Study was ended by new soproterenol tests after addtonal treatment for three days each wth terbutalne by nhalaton, two nhalatons four tmes daly (2 4 ) and sx nhalatons four tmes daly (6 4 ), respectvely. After the ntal soproterenol test (heavy sold curve n Fg 1 ), all patents were treated wth 5 mg of terbutalne sulfate orally three tmes daly. After 1, 2, 3, 6, 9, and 12 months of treatment wth terbutalne, the soproterenol test was re- per cent RELAXAnON Nonnat patents (n.eo) (_t1$.0.) -- Asthnatk pajents (..110m 3pa1.) CJ' oprenah L-base 9,m' FGURE 2. Relaxng effect of -soproterenol (soprenalne) sulfate on human bronchal muscle obtaned from normal and asthmatc patents and contracted wth carbachol (carbocholne) n vtro. Thck curve represents mean dose-response curve of 67 bronchal muscles from 60 patents wthout asthma; dagonally lned area ndcates ± SD. Other curves represent sx dose-response curves from three patents wth severe chronc asthma. 480 SVEDMYR, WSSON, THRNGER CHEST, 69: 4, APRL, 1976

3 peated usng exactly the same method. Pror to each soproterenol test, bronchodlator therapy was nterrupted for 12 hours. The study was performed over 12 months n an attempt to avod seasonal varatons n the basal degree of obstructon. After the test at 12 months, the patents were treated for three days wth two nhalatons of terbutalne. sulfate (0.50 mg ) four tmes daly (8 AM, 12 noon, 4 PM, and 8 PM) n addton to the oral terbutalne therapy. On the fourth day, a new soproterenol test was performed, Durng the followng three days, the patents were gven sx terbutalne nhalatons four tmes daly, and ths was followed by a fnal soproterenol test. n Vtro Tests RESULTS AND DSCUSSON The sx bronchal-muscle preparatons from the three asthmatc patents showed normal dose-response curves for soproterenol (Fg 2). Ths shows that there were no sgns of p-adrenergc blockade, despte the fact that these patents had pronounced arway obstructon and ded after surgery n respratory falure. n the early phase of an acute asthma attack, when bronchospasm domnates, patents also respond excellently to p-adrenergc stmulators. Ths pronounced bronchodlaton ndcates that p adrenergc blockade s not present n the bronchal muscle at ths stage. Treatment wth,a-adrenergc blockng drugs does not cause asthma n healthy ndvduals. Beta-adrenergc receptor blockade cannot, therefore, be the cause of asthma. Fgure 3 shows an experment from one of our prevous studes.v" n whch an a-adrenergc receptor stmulator, phenylephrne, dd not ntally cause contracton of untreated human bronchal muscle, whle a small dose of bacteral endotoxn ncreased the bronchoconstrctor effect of the a-adrenergc stmulator several thousand tmes. t would be of great nterest to know whether endotoxns ncrease a adrenergc medated lberaton of spasmogens n the bronchal muscle and, thereby, oppose the acton of 1 Q. 0.2 z 33' :>-7 ~ 'PHE PHE ~!! ,...,...,. a 3mn HSl 3.4'10-7 Q. 0 2 ~HST.! ~ e 7 1 ~ a 03mn ENOOTOX l a ~ 3mn?Y 17 10! FGURE 3. Effect of a-adrenergc receptor stfmulaton wth phenylephrne (PHE) n vtro on human bronchal muscle from patent wth chronc obstructve bronchts before and after addton of bacteral endotoxns (upper curoes) and senstvty for hstamne (HST) n same preparaton (lower curoes ). Concentratons are n grams per mlllter (from Smonsson, Svedmyr and Skoogh9 reproduced by permsson, Scand J Resp Ds). #-adrenergc stmulators. Ths mght be one of the causes of the so-called resstance to some,a-adrenergc stmulators. n Vvo Studes wth Terbutalne All patents stated mprovement of ther pulmonary functon throughout the perod of oral treatment wth terbutalne. Sometme durng the year of the study, most patents suffered from an acute nfecton, wth deteroraton for about a week, but conventonal antbotc therapy produced a rapd cure wthout necessty of changng the patents' basc therapy for asthma. n some cases a perod of nfecton occurred at a tme when the patent would otherwse have undergone an soproterenol test; ths was then postponed untl the nfecton had dsappeared. Fgure 1 shows the pulmonary functon expressed as FEV1.0. As may be seen, the patents had a relatvely mld basal obstructon, whch was a prerequste for admttance to the study; one would otherwse not have expected them to be able to carry out a year's treatment wthout alteraton of therapy. The thck sold curve shows the effect of the ntal soproterenol test; FEV1.0 ncreased wth the dose of soproterenol. Durng treatment wth terbutalne, the basal FEV1.0 values were equal to or hgher than those n the ntal test. Ths, n tself, suggests that the patents had not become resstant to ther own epnephrne (adrenalne) or norepnephrne ( noradrenaln ), whch, accordng to the resstance theory, mght be the cause of the ncrease n acute deaths. When soproterenol was subsequently nfused ntravenously, the FEV1.0 rose n the same way as n the ntal test, thus clearly demonstratng that resstance had not developed n the p-adrenergc receptors of the bronch durng long-term terbutalne therapy. Two curves (2 4 and 6 4) n Fgure 1 show the results when the patents had added treatment wth terbutalne by nhalaton, two nhalatons four tmes a day and sx nhalatons four tmes a day, respectvely. All patents stated that they experenced a further mprovement n ther pulmonary functon throughout. Three of the patents stated that they felt a transent mld rrtaton of the throat when they took sx nhalatons each tme. Fgure 2 also shows that basally the patents were objectvely mproved durng nhalaton therapy. Ths s n accordance wth our prevous fndngs" that the addton of nhalaton therapy mproves bronchodlaton. When soproterenol was nfused after the nhalaton seres, the same normal soproterenol effect was obtaned agan. There were no sgns of development of resstance n the p-adrenergc receptors of the bronch. There was no Sgnfcant dherence between the CHEST, 69: 4, APRL, 1976 DEVELOPMENT OF "RESSTANe.E" N BETA-ADRENERGC RECEPTORS 481

4 effect of soproterenol nfusons after two nhalatons four tmes daly and that after sx nhalatons four tmes daly. All patents developed pronounced muscular tremor towards the end of the ntal soproterenol test. The tremor was clearly vsble to the eye. Objectve regstraton (Fg 4) showed that the tremor was more than quadrupled wth' the hghest dose of soproterenol. The soproterenol-nduced muscular tremor decreased n all patents durng the course of "treatment wth terbutalne and was sgnfcantly less pronounced at all the subsequent soproterenol tests. On the average, tremor decreased by 50 percent. All patents also stated that tremor was most pronounced durng the frst two to three weeks of treatment wth terbualne. The effect on heart rate s shown n Fgure 5. All patents had almost constant basal heart rates at the varous tmes of nvestgaton, probably due to the fact that optmal basal condtons were acheved durng the performance of the tests. Durng the ntal soproterenol test, a pronounced ncrease n heart rate was recorded n all patents. Durng treatment wth terbutalne, the soproterenol-nduced ncrease n heart rate was less pronounced than durng the ntal test, but the dfference was not very marked. n studes n healthy subjects n the same age group, we have always found greater ncreases n heart rate wth the same doses of soproterenol than n patents wth arway obstructon. Ths suggests that the patents n the present study may have some TREMOR re. ampl., -soprenalne sulph.}jg. kg'. mn FGURE 4. Effects of -soproterenol (soprenalne) sulfate on muscular tremor n patents wth chronc asthma not prevously treated wth p-adrenergc stmulatng drugs ( thck curve) and after 1, 2, 3, 6, 9, and 12 months (,,, V, X, and X) of treatment wth terbutalne., T Heart rate beats/mn f ACKNOWLEDGMENTS: The skllful techncal assstance of Mrs. Lselott Magnusson and Mss Mare Hermansson s gratefully acknowledged. REFERENCES 1 Conolly ME, Daves DS, Dollery CT, et al: Resstance to p-adrenoceptor stmulants: A possble explanaton for the rse n asthma deaths. Br J Pharmacol43: , Szentvany A: The p-adrenergc theory of the atopc abnormalty n bronchal asthma. J Allergy 42 : , Alston WC, Patel KR, Kerr JW: Response of leukocyte adenyl cyclase to soprenalne and effect of A-blockng drugs n extrnsc bronchal asthma. Br Med J 1:90-93, soprenalne sulph. tjg kg- mn- 1 FGURE 5. Effects of -soproterenol (soprenalne) sulfate on heart rate n patents wth chronc asthma not prevously treated wth p-adrenergc stmulatng drugs (thck cume) and after 1, 2, 3, 6, 9, and 12 months (,,, V, X, and X) of treatment wth terbutalne. ntal resstance n the p-adrenergc receptors of the heart, possbly due to hgh sympathetc actvty n order to counteract ther arway obstructon. t s possble that resstance may also develop n the p-adrenergc receptors of the bronch f the patent very often takes large doses of a p-adrenergc stmulator; however, n our opnon, the so-called resstance found n patents wth very severe arway obstructon s n most cases due to other factors causng obstructon, such as mucosal edema and secretons, as ponted out prevously. Beta-adrenergc stmulators do not, of course, affect these factors. Ths development of "false" resstance warrants treatment wth other agents, such as sterods, antbotcs, and mucolytc agents. X V X 482 SYEDMYR, WSSON, THRNGER CHEST, 69: 4, APRL, 1976

5 4 Logsdon PJ, Carnrght DV, Mddleton E jr, et al: The effect of phentolamne on adenylate cyclase and on soproterenol stmulaton n leukocytes from asthmatc and nonasthmatc subjects. J Allergy Cln rnmunol 52: , Parker CW, Smth JW: Alteratons n cyclc adenosne monophosphate metabolsm n human bronchal asthma. J Cln nvest 52:48-59, Gllespe E, Valentne MD, Lchtensten LM: The fjadrenergc theory of asthma: Fact and fantasy. J Allergy Cln mmuno51:93-103, Coffey RG, Logsdon PJ, Mddleton E Jr: Leukocyte adenyl cyclase and ATPase n asthma: Effect of cortcosterod therapy. Chest 63 (suppl) :2S-3S, Svedmyr N: n general dscusson, Salbutamol symposum, London, Postgrad Med J 47 ( suppl) :120, Smonsson BG, Svedmyr N, Skoogh B-E, et al: n vvo and n vtro studes on a-receptors n human arways: Potentaton wth bacteral endotoxn. Scand J Respr Ds 53: , Svedmyr N, n dscusson. n Urley DM, Clarke SW, Cuthbert MF, et al (eds): Evaluaton of Bronchodlator Drugs: An Asthma Research Councl Symposum. London, Trust for Educaton and Research n Therapeutcs, Larsson S, Svedmyr N, Thrnger G: Studes of resstance for long-actng adrenergc fj-stmulators n asthmatc patents. Scand J Respr Ds 88( suppl) :58-59, Svedmyr N, Malmberg R, Thrnger G: The effect of a new adrenergc fj2-receptor stmulatng agent (rmterol, R798) n patents wth chronc obstructve lung dsease. Scand J Respr Ds 53: , Thrnger G, Svedmyr N: Evaluaton of skeletal muscle tremor due to bronchodlator agents. Scand J Respr Ds 56:2:93-102, Thrnger G, Svedmyr N: Comparson of.v, admnstered and nhaled terbutalne wth dose-effect curves n patents wth chronc obstructve lung dsease. Scand J Respr Ds 88 (suppl) :56-57, 1974 Knetc Art The knetc art of the present day ncludes works n vrtual and n actual movement n two or three dmensons. A sense of movement has been establshed through the actve partcpaton of the spectator-prncpally by hs movement n front of the work or by hs manpulaton of the elements nvolved n the work. n the case of threedmensonal works n real movement, there s an mportant dvson between machnes and mobles, whch depends upon ther greater or lesser degree of predctablty. The majorty of the machnes move n response to electro-magnetc forces. But human forces, hydraulc and magnetc forces, even solar forces and cybernetc devces also play ther part. Other forces of the physcal unverse were also beng used n the creaton of works of art that featured unpredctable movement. Water, fre and varous acds made a somewhat unexpected entry nto the feld of movement n art. The last group of mportant works wthn the overall feld of knetc art s concerned wth lght and movement. Works of ths knd can be traced back to three dfferent sources, the color organs, the cnema and the moble theatre set. On a relatvely small scale there were the "cnechromatc apparatuses," lumnous pctures, the "ehromoknetc" works and lght mobles, whch were equvalent to tradtonal pantngs n moton. Popper, F: Orgns and Development of Knetc Art (translated from French by Bann, S), New York, New York Graphc Socety, 1968 CHEST, 69: 4, APRL, 1976 DEVELOPMENT OF "RESSTANCE" N BETA-ADRENERGC RECEPTORS 483