Repeated challenge with dinitrobenzene sulphonic acid in dinitrofluorobenzene-sensitized mice results in vascular hyperpermeability in the trachea: arole for tachykinins

1 This study investigates the role of tachykinins in a repeated challenge w ith dinitrobenzene sulphonic acid (DNS) on the tracheal vascular permeabili ty in dinitrofluorobenzene (DNFB)sensitized mice. 2 DNFB-contact sensitization was followed by an intranasal (i.n.) challenge with DNS. A second challenge with DNS was administered 24 h after the firs t challenge. To assess changes in tracheal vascular permeability, Evans blu e dye accumulation in tracheal tissue was measured. 3 A repeated challenge with DNS in DNFB-sensitized mice led to a 2.8 fold i ncrease in tracheal vascular permeability when compared to DNFB-sensitized and vehicle-challenged mice or a 2.5 fold increase when compared to DNFB-se nsitized single DNS-challenged mice (P<0.001, ANOVA). 4 RP67580 (10(-9) mol mouse(-1) i.v.) reduced the increased tracheal vascul ar permeability induced by a second exposure to DNS in DNFB-sensitized mice completely when injected 15 min before the second challenge (P<0.001, ANOV A). 5 The increased tracheal vascular permeability response induced by the seco nd exposure to DNS could be mimicked with i.n. application of capsaicin (10 (-10) mol mouse(-1)) or substance P (SP) (10(-12) mol mouse(-1)) to DNFB-se nsitized and single DNS-challenged mice. 6 These results suggest that both tachykinin NK1 receptors and sensory nerv es are involved in the development of vascular hyperpermeability changes fo und in the trachea of DNFB-sensitized mice after a repeated DNS-challenge.