[Characteristics of the effect of ketotifen on the selective and non-selective histamine release from human basophils]

Administration of ketotifen at concentrations from 0.125 to 1.0 mM did not lead to the release of histamine from basophils of normal persons but induced a dose-dependent inhibition of histamine release provoked by IgE antibodies or Con A. The inhibitory action of ketotifen developed shortly after addition to the cells, being retained in the presence of the drug throughout the whole time of experiment (up to 40 min). Washing of the cells from ketotifen was followed by rapid recovery (at any rate within the first 5 min) of cell sensitivity to the histamine liberator. Ketotifen did not produce any influence on histamine release provoked by the cytotoxic secretion activators, chlorpromazine and mellitin.