"Functional antagonism" is often used to describe the general relaxant effect of beta 2 agonists and xanthines and their ability to protect the airways against bronchoconstrictor stimuli. This study in guinea pig isolated trachea addresses the question of whether the capacity of these drugs to protect against constrictor stimuli is related to smooth muscle relaxation. Three antimuscarinic drugs...

Induced bronchoconstriction in normal subjects can be transiently reversed by a deep breath (airway hysteresis). The mechanisms of airway hysteresis are not fully understood. The aim of these studies was to determine whether the nature of the deep breath (slow or fast inspiration, five or 10 second breath hold) affects the resultant bronchodilatation. Bronchoconstriction was induced in 10 norma...

BACKGROUND The i.v. anaesthetic propofol produces bronchodilatation. Airway relaxation involves reduced intracellular Ca(2+) ([Ca(2+)](i)) in airway smooth muscle (ASM) and lipid rafts (caveolae), and constitutional caveolin proteins regulate [Ca(2+)](i). We postulated that propofol-induced bronchodilatation involves caveolar disruption. METHODS Caveolar fractions of human ASM cells were test...

1 A'-trans-tetrahydrocannabinol, (A'-THC) produces bronchodilatation in asthmatic patients. 2 Administered in 63 jl metered volumes containing 50-200 jg by inhalation from an aerosol device to patients judged to be in a steady state, it increased peak expiratory flow rate (PEFR) and forced expiratory volume in 1 second (FEVI). 3 The rate of onset, magnitude, and duration of the bronchodilator e...

The bronchodilating efficacy of terbutaline (250 micrograms.puff) inhaled via the Nebuhaler and salbutamol (100 micrograms.puff) inhaled via the Volumatic has been studied in 30 patients with reversible obstructive airways disease in a randomized crossover study. The salbutamol/Volumatic combination produced significantly greater bronchodilatation than terbutaline/Nebuhaler (one puff, p less th...

In patients with acute severe asthma, 5 mg of terbutaline by inhalation and 500 microgram intravenously in divided doses both produced equally effective but not maximal bronchodilatation. There was no difference in the production of side-effects. These results support the view that inhaled therapy can be as effective in patients with acute severe asthma as injected treatment. In view of the ris...

As the existence of a late reaction in exercise induced asthma is controversial, peak expiratory flow (PEF) was measured for up to 13 hours after a running test in 404 consecutive young male army conscripts undergoing assessment of their asthma. In 294 subjects (73%) the immediate post-exercise fall in PEF was 10% or more; the mean (SD) fall in PEF in this group was 27% (15%). Nine patients wit...