Propranolol-induced hyperreactivity in guinea-pig lung parenchyma strips: possible role of histamine
Vanda, B.; Montaño, L.M.; Segura, P.; Rubio, H.; Selman, M.; Vargas, M.H.
Archives Internationales de Pharmacodynamie et de Therapie 319: 101-113
1992
ISSN/ISBN: 0003-9780 PMID: 1285669 Document Number: 400293
In vivo and in vitro studies have demonstrated that beta-adrenoceptor blockers enhance the airway smooth muscle contraction to antigen, but the mechanisms are not fully understood. In the present work, we corroborated that propranolol (3.9 x 10(-6) M, 30 min incubation) induces hyperreactivity to antigenic challenge (cumulative concentration-response curve to ovalbumin, 0.01 to 100 micrograms/ml) in lung parenchyma strips from sensitized guinea-pigs. This hyperreactivity was enhanced by indomethacin (3.2 x 10(-5) M) and was unaffected by the lipoxygenase/cyclooxygenase inhibitor phenidone (1 x 10(-4) M). However, the histamine H1 receptor antagonist pyrilamine (1 x 10(-6) M) reduced the potentiation effect of propranolol. These results suggest that bronchoconstrictor prostaglandins, thromboxane A2 and leukotrienes, are not involved in the propranolol-induced lung parenchyma strips hyperreactivity to antigen in vitro, and that histamine may account, at least in part, for such propranolol effect.