Abstract
Cell suspensions from the peritoneal cavity of rats are suitable preparations for the study of the release of physiologically active substances. The mast cells in these suspensions contain most of the histamine and 5-hydroxytryptamine, and all the extractable heparin. When subjected to incubation in the presence of base-type histamine liberators, lytic substances, dilution with distilled water, or freezing and thawing, histamine and 5-hydroxytryptamine are quantitatively released. The release of histamine and 5-hydroxytryptamine by histamine liberators is pH- and temperature-dependent. The release of these amines by procedures not involving the rupture of primary chemical bonds provides evidence that both amines are enclosed in a diffusible form or loosely bound, within the cell structure.