Rolipram inhibits airway microvascular leakage induced by platelet-activating factor, histamine and bradykinin in guinea-pigs.

Rolipram (0.1-1000 micrograms kg-1, i.v.) reduced the increase in microvascular permeability induced by platelet-activating factor (PAF; 50 ng kg-1, i.v.) at different sites of the guinea-pig airways. Rolipram (1-100 micrograms kg-1, i.v.) inhibited histamine (30 micrograms kg-1, i.v.)- and bradykinin (0.3 micrograms kg-1, i.v.)-induced airway microvascular leakage. These effects of rolipram were obtained at doses which inhibit histamine (7-20 micrograms kg-1 min-1)-induced bronchoconstriction (IC50 = 3 +/- 1 micrograms kg-1, i.v.) without depressing arterial blood pressure in the guinea-pig. Aminophylline (50 mg kg-1) did not change the effect of PAF. The anti-exudative effect of rolipram is of potential therapeutic value in asthma.