• 1 January 1982
    • journal article
    • research article
    • Vol. 46  (2) , 353-359
Abstract
Peritoneal mast cells from rats immunized with the nematode N. brasiliensis released histamine on challenge with antigen in both the presence and absence of added Ca. The response under the latter conditions was abolished by depletion of sequestered stores of the cation and probably reflected mobilization of these stores. The release was potentiated by brief pretreatment with chelating agents and inhibited (in the absence of phosphatidyl serine, PS) by supramaximal Ca concentrations. Ca bound to superficial sites in the membrane may then regulate the secretory process. Histamine release in both the presence and absence of Ca was enhanced by adenosine. Only the former response was potentiated by PS, in keeping with the view that the lipid promotes influx of the cation from the extracellualr environment. The activated state induced by antigen decayed with time but PS slowed this process. Histamine secretion in the absence of Ca was more rapid than in the presence of the cation, consistent with the release of bound Ca in a pulse of short duration.