Normal responsiveness of superficial hand veins to alpha- and beta-adrenergic stimuli in allergic asthma: effects of terbutaline and prednisolone on beta-adrenergic responsiveness.
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 alpha-adrenoceptor agonist, and to isoproterenol, a beta-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 (ED50) or in the maximal response (Emax) between the two groups. Bronchial hyperreactivity (assessed by methacholine-challenge tests) in the patients with asthma was uncorrelated with the ED50 or Emax of isoproterenol. These results demonstrate no evidence for a generalized change in alpha- or beta-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 beta-adrenoceptor desensitization in vivo. Local infusions of prednisolone or dexamethasone during 2 hours and systemic administration of dexamethasone (24 hours) caused a significant fall in the Emax for isoproterenol. The mechanism of attenuation of beta-adrenoceptor responsiveness by corticosteroids remains to be determined.
Eichler
H G
HG
Department of Medicine I, Vienna University Hospital, Austria.
Blöchl-Daum
B
B
Eichler
I
I
Wolzt
M
M
Korn
A
A
Götz
M
M
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D000704:Analysis of Variance; D001249:Asthma / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D005541:Forced Expiratory Volume / Q000187:drug effects; D006225:Hand / Q000098:blood supply; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008688:Methacholine Compounds / Q000008:administration & dosage; D010656:Phenylephrine / Q000494:pharmacology; D011239:Prednisolone / Q000494:pharmacology*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D013726:Terbutaline / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D008688:Methacholine Compounds; D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; D011239:Prednisolone; D007545:Isoproterenol; D013726:Terbutaline