Acute and chronic treatment with glucocorticosteroids, modifying the beta 2-adrenergic response of the guinea pig trachea.
The effect of beta 2-adrenoceptor agonists on airway smooth muscle relaxation may be subject to desensitization. It could be modified by glucocorticosteroid treatment. An increase in the beta 2 agonist response by glucocorticosteroids in vitro has been described. We studied the effects of acute and chronic treatment with dexamethasone on the relaxation response of tracheal smooth muscle to beta 2 agonists, fenoterol and salbutamol. Fenoterol showed a greater force of relaxation than salbutamol, and both drugs induced desensitization. Acute treatment with dexamethasone reduced desensitization to both beta 2 agonists. Chronic treatment (120 micrograms/kg of dexamethasone for 7 days) reduced the desensitization to fenoterol alone. Dexamethasone (200 micrograms/kg for 7 days) increased relaxation to salbutamol and reduced desensitization to both drugs. The interaction between beta 2 agonists and glucocorticosteroids could be important in the clinical use of both drugs in the treatment of asthma.
Seco
A J
AJ
Departamento de Medicina, Farmacologia, Facultad de Medicina, Oviedo, Spain.
Salgueiro
M E
ME
Manso
G
G
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000403:Airway Resistance / Q000187:drug effects*; D000420:Albuterol / Q000494:pharmacology; D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005280:Fenoterol / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects; D018343:Receptors, Adrenergic, beta-2 / Q000187:drug effects*; D014132:Trachea / Q000187:drug effects
D000318:Adrenergic beta-Agonists; D005938:Glucocorticoids; D018343:Receptors, Adrenergic, beta-2; D005280:Fenoterol; D003907:Dexamethasone; D000420:Albuterol