Propranolol-induced hyperreactivity in guinea-pig lung parenchyma strips: possible role of histamine.
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.
Vanda
B
B
Instituto Nacional de Enfermedades Respiratorias, Unidad de Investigación, México, DF.
Montaño
L M
LM
Segura
P
P
Rubio
H
H
Selman
M
M
Vargas
M H
MH
D000818:Animals; D006168:Guinea Pigs; D006632:Histamine / Q000502:physiology*; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008168:Lung / Q000187:drug effects*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D010047:Ovalbumin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology*; D011738:Pyrilamine / Q000494:pharmacology; D011969:Receptors, Histamine H1 / Q000187:drug effects
D011969:Receptors, Histamine H1; D006632:Histamine; D010047:Ovalbumin; D011433:Propranolol; D011738:Pyrilamine; D007213:Indomethacin