title: Effect of ketotifen and oxatomide on histamine secretion from mast cells.
abstract: The anti-histaminic drugs ketotifen and oxatomide have a dual effect on rat peritoneal mast cells. At high concentrations they induce histamine release, whereas at low concentrations they inhibit secretion evoked by IgE-directed ligands. The latter effect is observed in the presence and absence of exogenous calcium. The significance of this result for the general mode of action of anti-anaphylactic drugs is discussed. Neither compound liberates histamine from isolated mesenteric cells from the rat or guinea pig, further emphasizing the functional heterogeneity of mast cells from different sources.
mesh_terms: D000818:Animals; D006634:Histamine H1 Antagonists / Q000494:pharmacology*; D006636:Histamine Release / Q000187:drug effects*; D007073:Immunoglobulin E / Q000502:physiology; D066298:In Vitro Techniques; D007665:Ketotifen / Q000494:pharmacology*; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D006634:Histamine H1 Antagonists; D010879:Piperazines; D007073:Immunoglobulin E; C015408:oxatomide; D007665:Ketotifen