Modulation of beta 2-adrenoceptors in human lymphocytes by in vitro stimulation with mediators.
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.
Sanz
M L
ML
Department of Allergology and Clinical Immunology, School of Medicine, University of Navarra, Pamplona, Spain.
de la Cuesta
C G
CG
Oehling
A
A
D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D006632:Histamine / Q000494:pharmacology*; D006636:Histamine Release; D006801:Humans; D017998:Leukotriene D4 / Q000494:pharmacology*; D008555:Melitten / Q000494:pharmacology*; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D010972:Platelet Activating Factor / Q000494:pharmacology*; D018343:Receptors, Adrenergic, beta-2 / Q000096:biosynthesis*
D010972:Platelet Activating Factor; D018343:Receptors, Adrenergic, beta-2; D008555:Melitten; D017998:Leukotriene D4; D006632:Histamine; D010741:Phospholipases A; D054467:Phospholipases A2