Abstract
Antigen-induced histamine release from human skin passively sensitized with antigen-spesific IgE antibody was inhibited by drugs (catecholamines and methylxanthines) which increase the cellular concentration of cyclic AMP. Adrenaline and theophylline inhibited antigen-induced histamine release from passively sensitized human skin in a dose-related manner. That the inhibitory effect of adrenaline is due to β-adrenergic stimulation was established using the specific β-adrenergic blocking agent propranolol. A marked synergism was observed when adrenaline and theophylline were used together. In further experiments dibutyryl cyclic AMP also inhibited antigen-induced histamine release from human skin. These results raise the posibility that cyclic AMP exerts a regulatory effect on IgE-mediated hypersensitivity in human skin. Cytochalasin B which selectively inhibits the function of contractile microfilaments of cells inhibited the antigen-induced histamine release from passively sensitized human skin. The inhibitory effect of cytochalasin B on antigen-induced histamine release was reversible. These results indicate that the inhibition of antigen-induced histamine release from sensitized human skin by cytochalasin B may be due to the inhibition of function of contractile microfilaments in sensitized target cells by cytochalasin B.
