| Autor: |
Manfred Götz, Brigitte Blöchl-Daum, Irmgard Eichler, A. Korn, Hans-Georg Eichler, Michael Wolzt |
| Rok vydání: |
1990 |
| Předmět: |
|
| Zdroj: |
Journal of Allergy and Clinical Immunology. 86:714-725 |
| ISSN: |
0091-6749 |
| DOI: |
10.1016/s0091-6749(05)80175-7 |
| Popis: |
Impaired function of the adrenergic-receptor system has been postulated to contribute to the pathogenesis of bronchial asthma. Using the dorsal hand-vein compliance technique, we compared the changes in diameter of superficial hand veins in response to phenylephrine, an α-adrenoceptor agonist, and to isoproterenol, a β-adrenoceptor agonist, in 14 untreated patients with allergic asthma and in 16 nonatopic control subjects. There were no significant differences in the median effective dose of phenylephrine that produced 50% of maximal venoconstriction (ED 50 ) or in the maximal response (E max ) between the two groups. Bronchial hyperreactivity (assessed by methacholine-challenge tests) in the patients with asthma was uncorrelated with the ED 50 or E max of isoproterenol. These results demonstrate no evidence for a generalized change in α-or β-adrenergic responsiveness on smooth muscle cells in asthma. Hand-vein responsiveness to isoproterenol was unchanged after treatment for 7 days with oral terbutaline (5 mg three times per day). Thus unlike leukocytes, smooth muscle appears not readily susceptible to β-adrenoceptor densensitization in vivo. Local infusions of prednisolone or dexamethasone during 2 hours and systemic administration of dexamethasone (24 hours) caused a significant fall in the E max for isoproterenol. The mechanism of attenuation of β-adrenoceptor responsiveness by corticosteroids remains to be determined. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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