Storage Properties of Rat Mast Cell Granules In vitro

Basophil granules were isolated from rat peritoneal and thoracic mast cells. The granules were depleted of their endogenous Hi and 5‐HT. The uptake of Hi, 5‐HT, TrpA, PhEA, TA, DA, NA, ACh, Na and Ca (for abbreviations see page 215) by the depleted granules, the release of Hi from Hi‐recharged granules by Ca, Na and K and the competition between NA and Hi, ACh and NA, ACh and Hi for the granule storage sites were studied. The results support the hypothesis that these granule stores have the properties of a weak cation exchange resin. Furthermore it was found that amphetamine and ephedrine competed with NA for the storage sites The results indicate an unspecific granule storage of cations—organic and inorganic—differing only in their affinities for the binding sites.