Skin responses to bradykinin, kallidin, and [desArg9]-bradykinin in nonatopic and atopic volunteers.

Abstract

Kinins are potent vasoactive oligopeptides that may act as mediators in a variety of inflammatory diseases of the skin by interacting with specific receptors designated B1 and B2. In this study we have investigated the structure-activity relationship of intradermally injected bradykinin, kallidin (lysine-bradykinin), and [desArg9]-bradykinin in atopic (n = 8) and nonatopic (n = 8) subjects. On two separate occasions, each separated by a week, subjects randomly underwent intradermal challenge with incremental doses (0.5, 5, and 50 nmol) of either the B1-agonist [desArg9]-bradykinin, the B2-agonists bradykinin or kallidin, or vehicle placebo. In a separate randomized double-blind study we have also examined the effect of an orally administered antihistamine, terfenadine, on kinin-induced wheal and flare responses and their repeatability in a group of nine volunteers. The skin responses were monitored objectively by measurement of wheal and flare areas. Both bradykinin and kallidin induced a dose-dependent increase in wheal and flare areas in all subjects studied. Although the effects of the two lowest doses (0.5 and 5 nmol) of [desArg9]-bradykinin on skin responses were indistinguishable from those of placebo, this kinin at the highest dose administered (50 nmol) caused a significant increase in wheal and flare areas in all subjects studied. No difference could be identified in the skin responses to kinins between atopic and nonatopic subjects. In addition kinin-induced cutaneous responses were not altered by pretreatment with terfenadine. These in vivo structure activity studies suggest that in human beings the skin responses to kinins may be compatible with the stimulation of B2 receptors, which is unrelated to histamine release from cutaneous mast cells.