Delayed‐type hypersensitivity‐induced increase in vascular permeability in the mouse small intestine: inhibition by depletion of sensory neuropeptides and NK1 receptor blockade

1 This study investigates the effects of capsaicin‐induced depletion of sensory neuropeptides and of neurokinin! (NK1) receptor blockade on delayed‐type hypersensitivity (DTH)‐induced changes of vascular permeability in the small intestine of the mouse. 2 The DTH reaction in the small intestine was elicited by dinitrofluorobenzene (DNFB)‐contact sensitization followed by oral dinitrobenzene sulphonic acid (DNBS) challenge. To assess vascular leakage the accumulation of the plasma marker, Evans blue (EB), was measured 2, 24 and 48 h after the challenge. 3 The small intestinal DTH reaction was characterized by a significant increase in vascular permeability 24 h after the challenge of previously sensitized mice when compared to vehicle‐sensitized mice (P