Ml. Sanz et al., MODULATION OF BETA-2-ADRENOCEPTORS IN HUMAN-LYMPHOCYTES BY IN-VITRO STIMULATION WITH MEDIATORS, Journal of investigational allergology & clinical immunology, 4(3), 1994, pp. 116-121
Since Szentivanyi established the beta-adrenergic theory, many attempt
s 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 postul
ated that this might be due to mediator activity. Blood was extracted
from 46 healthy donors for this study. Radioligand [I-125]-iodocyanopi
ndolol was used for beta-adrenoceptor determination in peripheral bloo
d 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 meli
ttin (phospholipase A2, PLA2, activator) exposure. A significant decre
ase was obtained after histamine (p < 0.05), LTD4 (p < 0.05) and melit
tin (p < 0.001) exposure; PAF did not modify the number of beta-adreno
ceptors. In conclusion, our results confirm that down-regulation of be
ta-adrenoceptors can be induced by mediator release