Modulation of beta 2-adrenoceptors in human lymphocytes by in vitro stimulation with mediators
Sanz ML, de la Cuesta CG, Oehling A.
Department of Allergology and Clinical Immunology, School of Medicine, University of Navarra, Pamplona, Spain
Since Szentivanyi established the beta-adrenergic theory, many attempts have been made to explain the dynamics of bronchial hyperreactivity and cytotropic allergic reaction by this mechanism. In previous work, we found that beta-adrenoceptor numbers were decreased in symptomatic patients and after specific antigenic exposure.
As a result, we postulated that this might be due to mediator activity. Blood was extracted from 46 healthy donors for this study. Radioligand [125I]-iodocyanopindolol was used for beta-adrenoceptor determination in peripheral blood lymphocytes following Brodde's method.
Student's t test was used for statistical analysis. beta-Adrenoceptor number was determined before and after exposure to mediators (histamine, PAF, LTD4), and after melittin (phospholipase A2, PLA2, activator) exposure. A significant decrease was obtained after histamine (p < 0.05), LTD4 (p < 0.05) and melittin (p < 0.001) exposure; PAF did not modify the number of beta-adrenoceptors.
In conclusion, our results confirm that down-regulation of beta-adrenoceptors can be induced by mediator release.
CITATION J Investig Allergol Clin Immunol. 1994 May-Jun;4(3):116-21