Abstract
The effect of different histamine liberators on isolated peritoneal mast cells of the mouse and rat has been examined. Both cell types responded to the lectin, concanavalin A, and the release was in each case potentiated by phosphatidylserine. The rat cells released histamine on treatment with dextran but the mouse cells were essentially refractory to the polysaccharide. The mouse cells were significantly more responsive to the actions of the ionophore A23187 and adenosine 5′-triphosphate but much less reactive towards the polycations, compound 48/80 and peptide 401 (the MCD-peptide from bee venom). The reactivity of the mouse cells towards the latter two agents was enhanced in the absence of extracellular calcium. These results further emphasize the functional heterogeneity of mast cells from different sources.