ROLIPRAM INHIBITS AIRWAY MICROVASCULAR LEAKAGE INDUCED BY PLATELET-ACTIVATING-FACTOR, HISTAMINE AND BRADYKININ IN GUINEA-PIGS

Rolipram (0.1-1000 mu g kg(-1), i.v.) reduced the increase in microvas cular permeability induced by platelet-activating factor (PAF; 50 ng k g(-1), i.v.) at different sites of the guinea-pig airways. Rolipram (1 -100 mu g kg(-1), i.v.) inhibited histamine (30 mu g kg(-1), i.v.)- an d bradykinin (0.3 mu g kg(-1), i.v.)-induced airway microvascular leak age. These effects of rolipram were obtained at doses which inhibit hi stamine (7-20 mu g kg(-1) min(-1))-induced bronchoconstriction (IC50=3 +/-1 mu g 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 therape utic value in asthma.