Regulation of human basophil activation. IV. Dissociation between cationic dye binding and histamine release: role of Ca2+ ions.

摘要: In previous studies we observed that in vitro histamine release from human basophils could be dissociated the loss of affinity basophil granules for a cationic dye, toluidine blue. present study further explored intracellular signals leading to decrease blue positive (TB+) numbers, with or without release. Since Ca2+ mobilization is crucial event secretion and particularly release, studied role as compared TB+ decrease. presence external (2 mM): i) channel antagonists verapamil nifedipine up 10 microM were effect on IgE-mediated decrease; ii) loading leucocytes Quin2 preincubation TMP-8, an internal antagonist, significantly inhibited basophils. absence added Ca2+:i) was abolished whereas not modified, even EGTA;ii) by prolonged EGTA preincubation, incubation TMB-8. We conclude requires both influx Ca2+. contrast, no required which, however, appears play important role.