Pharmacological activity of bamifylline on lung anaphylaxis: in vitro studies

Bamifylline, a 7-8 disubstituted theophylline derivative, reduces in a dose dependent way (1 x 10(-5) M, 1 x 10(-4) M and 1 x 10(-3) M) the release of histamine, TXB2 (measured also as TXA2-like material) and SRS-A (as LTD4-like material) during the immunological challenge of actively sensitized guinea-pig lungs perfused in vitro. Theophylline was significantly less potent than bamifylline and particularly, at the higher concentrations used (1 x 10(-3) M), bamifylline was 2.7 times more potent than theophylline in reducing the immunological release of histamine and 1.6 and 1.5 times more potent in inhibiting the production of TXB2 and SRS-A, respectively. These data suggest that the ability of the two xanthine derivatives to control the immunological release of histamine represents an important point in understanding the mechanism of their anti-anaphylactic activity.