Pharmacological activity of bamifylline on lung anaphylaxis: In vitro studies

Bamifylline, a 7–8 disubstituted theophylline derivative, reduces in a dose dependent way (1 × 10 −5 m, 1 × 10 −4 m and 1 × 10 −3 m) the release of histamine, TXB 2 (measured also as TXA 2-like material) and SRS -A (as LTD 4 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 × 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 TXB 2 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.