Some further characteristics of histamine secretion from rat mast cells stimulated with sodium orthovanadate.

Sodium orthovanadate induced a release of histamine from rat peritoneal mast cells. Other oxyanions of vanadium with the metal in the +V oxidation state also evoked histamine release but neither vanadyl sulphate (+IV oxidation state) nor the analogous orthophosphate anion were effective secretagogues. The release evoked by vanadate was selectively inhibited by the anion channel blocker SITS, and by theophylline and Bu2cAMP, but was unaffected by disodium cromoglycate and lanthanum ions. These results are discussed in terms of the possible mode of action of vanadate.