The Effect of Regular Inhaled Salbutamol on the Airway Responsiveness of Normal Subjects

1982 ◽  
Vol 63 (6) ◽  
pp. 513-517
Author(s):  
C. M. B. Higgs ◽  
R. B. Richardson ◽  
G. Laszlo
Keyword(s):  
Sodium Cromoglycate ◽  
Beclomethasone Dipropionate ◽  
Normal Subjects ◽  
Airway Responsiveness ◽  
Regular Treatment ◽  
Development Of Resistance ◽  
Airway Response ◽  
Airway Responses ◽  
To Receive ◽  
Inhaled Salbutamol

1. Airway responses to inhaled salbutamol were measured in two groups of six normal non-atopic subjects. In each group there was a dose-dependent increase in specific airways conductance after salbutamol inhaled in cumulative doses from 25 to 600 μg. 2. In the first group these studies were repeated weekly during and after the subjects had taken regular inhaled salbutamol for 4 weeks, in doses increasing to 500 μg four times daily by week 4. Then, while subjects were continuing to receive regular salbutamol, the studies were repeated after 48 h of inhaled sodium cromoglycate (20 mg four times daily) and again after 48 h of beclomethasone dipropionate (200 μg four times daily). 3. In the second group the studies were repeated after 10 days of regular inhaled salbutamol (500 μg four times daily). 4. There was no change in airway response to inhaled salbutamol after 4 weeks or 10 days regular salbutamol therapy, or after 48 h of sodium cromoglycate or beclomethasone dipropionate therapy. 5. This study did not show the development of resistance to β-agonists in the airways of normal subjects. These findings are discussed in the context of other studies which have shown the development of resistance, and we suggest that there may be a spectrum of susceptibility to the development of impaired airway responsiveness following regular treatment with β-adrenergic drugs.

Bronchoprotective and bronchodilatory effects of deep inspiration in rabbits subjected to bronchial challenge

2001 ◽  
Vol 91 (6) ◽  
pp. 2511-2516 ◽  
Author(s):  
S. J. Gunst ◽  
X. Shen ◽  
R. Ramchandani ◽  
R. S. Tepper
Keyword(s):  
Human Subjects ◽  
Inhibitory Effect ◽  
Airway Responsiveness ◽  
Deep Inspiration ◽  
Contractile Apparatus ◽  
Airway Reactivity ◽  
Airway Response ◽  
Normal Human ◽  
Airway Responses

The effect of deep inspiration (DI) on airway responsiveness differs in asthmatic and normal human subjects. The mechanism for the effects of DI on airway responsiveness in vivo has not been identified. To elucidate potential mechanisms, we compared the effects of DI imposed before or during induced bronchoconstriction on the airway response to methacholine (MCh) in rabbits. The changes in airway resistance in response to intravenous MCh were continuously monitored. DI depressed the maximum response to MCh when imposed before or during the MCh challenge; however, the inhibitory effect of DI was greater when imposed during bronchoconstriction. Because immature rabbits have greater airway reactivity than mature rabbits, we compared the effects of DI on their airway responses. No differences were observed. Our results suggest that the mechanisms by which DI inhibits airway responsiveness do not depend on prior activation of airway smooth muscle (ASM). These results are consistent with the possibility that reorganization of the contractile apparatus caused by stretch of ASM during DI contributes to depression of the airway response.

Airway and Metabolic Responsiveness to Intravenous Salbutamol in Asthma: Effect of Regular Inhaled Salbutamol

1981 ◽  
Vol 60 (5) ◽  
pp. 579-585 ◽  
Author(s):  
J. E. Harvey ◽  
C. J. Baldwin ◽  
P. J. Wood ◽  
K. G. M. M. Alberti ◽  
A. E. Tattersfield
Keyword(s):  
Fatty Acids ◽  
Cyclic Nucleotide ◽  
Response Curve ◽  
Normal Subjects ◽  
Asthmatic Patients ◽  
Esterified Fatty Acids ◽  
Show Evidence ◽  
Airway Response ◽  
Adrenoceptor Agonists ◽  
Inhaled Salbutamol

1. Airway, metabolic and cyclic nucleotide responses to intravenous salbutamol were measured in five patients with mild asthma who had taken no medication in the week before the study. The studies were repeated after the patient had taken regular inhaled salbutamol for 4 weeks, in doses increasing to 2000 μg daily in week 4. 2. The pretreatment airway, metabolic and cyclic nucleotide responses to salbutamol were similar to those previously reported in normal subjects. These patients therefore did not show evidence of partial β-adrenoceptor blockade. 3. After 4 weeks' salbutamol therapy the airway response to intravenous salbutamol was unchanged. 4. The glucose, pyruvate and adenosine 3′:5′-cyclic monophosphate (cyclic AMP) responses to intravenous salbutamol were depressed after regular salbutamol administration. The dose-response curve for non-esterified fatty acids and insulin, though displaced downwards, did not indicate an impaired response to salbutamol since the shape was unchanged. There was no significant change in the lactate, glycerol and total ketone response. 5. This study confirms that tissues differ in the ease with which they develop resistance to β-adrenoceptor agonists. Asthmatic airways appear to be relatively protected from developing resistance when compared with other tissues in asthmatic patients and when compared with the airways of normal subjects.

scholarly journals Salmeterol and Airway Response to Allergen

1997 ◽  
Vol 4 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Donald W Cockcroft ◽  
Veronica A Swystun ◽  
Rajesh Bhagat ◽  
Sanjay Kalra
Keyword(s):  
Inhaled Corticosteroids ◽  
Day Treatment ◽  
Tertiary Care ◽  
Forced Expiratory Volume ◽  
Airway Responsiveness ◽  
Double Blind ◽  
Regular Treatment ◽  
Beta Agonists ◽  
Randomized Crossover Trial ◽  
Airway Response

BACKGROUND: Regular treatment with inhaled salbutamol (seven to 14 days) increases airway responsiveness to allergen.OBJECTIVE: To assess the effect of salmeterol 50 µg twice daily for six days on the early asthmatic response to allergen (PC15).DESIGN: Double-blind, randomized, crossover trial comparing salmeterol with placebo (twice daily over six days) with one week or more washout. Forced expiratory volume in 1 s (FEV1) and allergen PC15were measured 36 h after each treatment was discontinued.SETTING: Tertiary care out-patient bronchoprovocation laboratory.SUBJECTS: Fourteen atopic asthmatics well controlled with (n=5) or without (n=9) inhaled corticosteroids. Subjects did not use inhaled beta-agonists for at least two weeks before and during the trial.RESULTS: FEV1was slightly but significantly lower 36 h after the last dose of salmeterol versus placebo (3.28±0.83 versus 3.40±0.88 L, P=0.032). Airway responsiveness to allergen increased by about half a doubling concentration (log10PC152.71±0.61 versus 2.85±0.61, P=0.047).CONCLUSION: A six-day treatment course of salmeterol 50 μg twice daily resulted in a slight decline in FEV1and a modest increase in airway response to allergen at 36 h.

Pattern and mechanism of airway response to hypocapnia in normal subjects

1979 ◽  
Vol 47 (1) ◽  
pp. 8-12 ◽  
Author(s):  
C. F. O'Cain ◽  
M. J. Hensley ◽  
E. R. McFadden ◽  
R. H. Ingram
Keyword(s):  
Vital Capacity ◽  
Normal Subjects ◽  
Oxygen Mixture ◽  
Flow Volume ◽  
Mixture Density ◽  
Lung Capacity ◽  
Airway Constriction ◽  
Maximal Expiratory Flow ◽  
Airway Response ◽  
Expiratory Flow

We examined the bronchoconstriction produced by airway hypocapnia in normal subjects. Maximal expiratory flow at 25% vital capacity on partial expiratory flow-volume (PEFV) curves fell during hypocapnia both on air and on an 80% helium- 20% oxygen mixture. Density dependence also fell, suggesting predominantly small airway constriction. The changes seen on PEFV curves were not found on maximal expiratory flow-volume curves, indicating the inhalation to total lung capacity substantially reversed the constriction. Pretreatment with a beta-sympathomimetic agent blocked the response, whereas atropine pretreatment did not, suggesting that hypocapnia affects airway smooth muscle directly, not via cholinergic efferents.

Effects of elastase-induced emphysema on airway responsiveness to methacholine in rats

1989 ◽  
Vol 66 (2) ◽  
pp. 606-612 ◽  
Author(s):  
S. Bellofiore ◽  
D. H. Eidelman ◽  
P. T. Macklem ◽  
J. G. Martin
Keyword(s):  
Lung Volume ◽  
Brown Norway ◽  
Pulmonary Mechanics ◽  
Maximum Increase ◽  
Before And After ◽  
Airway Response ◽  
Residual Capacity ◽  
Airway Responses ◽  
Norway Rats ◽  
Concentration Response Curve

We examined the effects of elastase-induced emphysema on lung volumes, pulmonary mechanics, and airway responses to inhaled methacholine (MCh) of nine male Brown Norway rats. Measurements were made before and weekly for 4 wk after elastase in five rats. In four rats measurements were made before and at 3 wk after elastase; in these same animals the effects of changes in end-expiratory lung volume on the airway responses to MCh were evaluated before and after elastase. Airway responses were determined from peak pulmonary resistance (RL) calculated after 30-s aerosolizations of saline and doubling concentrations of MCh from 1 to 64 mg/ml. Porcine pancreatic elastase (1 IU/g) was administered intratracheally. Before elastase RL rose from 0.20 +/- 0.02 cmH2O.ml-1.s (mean +/- SE; n = 9) to 0.57 +/- 0.06 after MCh (64 mg/ml). A plateau was observed in the concentration-response curve. Static compliance and the maximum increase in RL (delta RL64) were significantly correlated (r = 0.799, P less than 0.01). Three weeks after elastase the maximal airway response to MCh was enhanced and no plateau was observed; delta RL64 was 0.78 +/- 0.07 cmH2O.ml-1.s, significantly higher than control delta RL64 (0.36 +/- 0.7, P less than 0.05). Before elastase, increase of end-expiratory lung volume to functional residual capacity + 1.56 ml (+/- 0.08 ml) significantly reduced RL at 64 mg MCh/ml from 0.62 +/- 0.05 cmH2O.ml-1.s to 0.50 +/- 0.03, P less than 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

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