Figure 3.

Effect of ovalbumin (1 mg kg⁻¹ i.v.), LTD₄ (0.001 – 0.05 mg kg⁻¹ i.v.), 5-HT (0.03 – 3 mg kg⁻¹ i.v.) or histamine (0.3 – 30 mg kg⁻¹ i.v.) on microvascular leakage into the (a) trachea, (b) bronchi or (c) intra-pulmonary airways of antigen-sensitized Brown Norway rats. Rats were anaesthetized with isofluorane (3.5% in oxygen) and received Evans blue (20 mg kg⁻¹ i.v.), 1 min later they received ovalbumin, LTD₄, 5-HT, histamine or vehicle i.v. The rats were killed 15 min after ovalbumin or mediator administration and tissues removed and placed in formamide for Evans blue dye extraction. Values are presented as data minus basal leak at time 0 and expressed as mean±s.e.mean of the concentration of Evans blue dye (ng mg⁻¹ of tissue). n=4. ^*P<0.05, ^**P<0.01, ^***P<0.001.