title: Study of the mechanism of inhibitory action of tranilast on chemical mediator release.
abstract: We investigated the mechanism of inhibitory action of tranilast on chemical mediator release by antigen-antibody reactions. Tranilast (10(-5)-10(-3) M) inhibited antigen (DNP-Ascaris)-induced histamine release from sensitized purified rat mast cells (PMC), but did not show an obvious influence on intracellular cyclic AMP. 45Ca uptake into PMC induced by antigen (300 micrograms/ml) was obviously suppressed by tranilast (10(-6)-10(-3) M). Tranilast (10(-4) M) inhibited antigen-induced histamine release from and 45Ca uptake into PMC independently of the presence or absence of glucose in the medium. On the other hand, 2-deoxyglucose (10(-2) M) markedly inhibited both responses in the absence but not in the presence of glucose. Tranilast slightly inhibited Ca-induced contraction of guinea pig taenia coli, but had no influence on aggregation of rabbit platelets. Verapamil (10(-6)-10(-4) M) had no effect on antigen-induced histamine release, but it markedly suppressed Ca-induced contraction and platelet aggregation. From these results, we suggest that the mechanism of inhibitory action of tranilast on the release of antigen-induced chemical mediator from mast cells involves the suppression of Ca uptake, but that its mode of action is apparently different from those of 2-deoxyglucose and verapamil.
mesh_terms: D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002132:Calcium Radioisotopes; D000242:Cyclic AMP / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology; D006168:Guinea Pigs; D006633:Histamine Antagonists / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D014700:Verapamil / Q000494:pharmacology; D062367:ortho-Aminobenzoates / Q000494:pharmacology*
chemical_list: D002132:Calcium Radioisotopes; D006633:Histamine Antagonists; D062367:ortho-Aminobenzoates; D000968:Antimycin A; D014700:Verapamil; D000242:Cyclic AMP; C012293:tranilast; D005947:Glucose; D002118:Calcium