ISSN:
1432-1076
Keywords:
Asthmatic children
;
β-Adrenoceptors
;
β-Sympathomimetic drugs
;
Lung function
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Clinical observations have shown that some asthma patients develop tachyphylaxis to β-sympathomimetic drugs. As down-regulation of the number of β-adrenoceptors in different human tissues after exposure to catecholamines and β-adrenergic drugs is well known, we investigated whether a interrelation exists between β-adrenoceptor down-regulation and clinically detectable β-adrenergic subsensitivity during β-sympathomimetic treatment. The following results were obtained: 1. β2-Sympathomimetic inhalation treatment with salbutamol in therapeutic doses led to a significant downregulation of β2-adrenoceptors and consecutive cyclic adenosine monophosphate response to isoprenaline. This effect was already detectable after short-term treatment of 3–7 days in 9 asthmatic children. 2. In the long-term study over 6 months, salbutamol inhalation in 12 asthmatic children led to a significant down-regulation of β-adrenoceptor binding sites on mononuclear blood cells (MNC) from 1539±91 to 1115±99 after 14 days, remaining in this range thereafter. 3. The mean airway resistance (Raw) of these 12 patients decreased significantly within 14 days from 8.1±0.8 to 5.7±0.5 cm H2O/l/s to remain stable throughout the 6 months of salbutamol treatment. The differences in Raw before and immediately after inhalation of 0.2 mg salbutamol (2 puffs) were unchanged during the study period. It is concluded, that long-term inhalative treatment with salbutamol over a period of 6 months does not result in refractoriness to β-adrenergic drugs in the airways of asthmatic children, even though a significant down-regulation of β2-receptors on peripheral MNC occurs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01963569
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