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Ionic regulation of human basophil releasability. II. Non‐releasing basophils are converted into releasing basophils in a low‐Na + medium
Author(s) -
TEDESCHI A.,
ARQUATI M.,
PALELLA M.,
MILAZZO N.,
MIADONNA A.
Publication year - 1994
Publication title -
clinical and experimental allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 154
eISSN - 1365-2222
pISSN - 0954-7894
DOI - 10.1111/j.1365-2222.1994.tb00919.x
Subject(s) - histamine , chemistry , extracellular , basophil , immunoglobulin e , incubation , stimulation , endocrinology , medicine , pharmacology , biochemistry , immunology , biology , antibody
Summary The effects of different extracellular Na + and CV 2+ concentrations on histamine release from human basophils were investigated. Isosmotic replacement of extracellular Na + either with choline + , a non‐permeant Na + analogue, or glucose significantly increased spontaneous and anti‐IgE‐induced histamine release. Basophils from 12 of 49 normal subjects, which were found not to release histamine upon challenge with an optimal dose of anti‐IgE in a 135 mM NaCl buffer, were converted into releasing basophils when stimulation with anti‐IgE was performed in a low‐Na + medium. The increase in Na + concentration in the extracellular medium was accompanied by a reduction in the magnitude of basophil response to anti‐IgE, which was significantly more pronounced in non‐releasers than in releasers (per cent inhibition by 70 mM NaCl 75.5 + 3.2 vs 43.5 + 9.0, P < 0.01). At higher Na + concentrations a progressive and almost complete abrogation of histamine release was observed in non‐releasers, but not in releasers (maximal per cent inhibition at 140 mM NaCl 97.3+1.3 vs 50.4 + 8.6). The Na + /H + exchanger monensin had a dose‐dependent inhibitory effect on anti‐IgE‐induced histamine release, and the concentration inhibiting 50% of histamine release was l.5 × 10 −7 M. When basophils were challenged in the presence of different Na + and C 2+ concentrations, it was shown that the two cations have antagonistic effects, which is to say that they down‐regulate and upregulate histamine release, respectively. Moreover, the requirement of extracellular Ca 2+ was lowered in a low‐Na + medium. These results suggest that Na + and Ca + ions contribute with opposite effects to the modulation of basophil response to anti‐IgE and that non‐releasing basophils are converted into releasing basophils in a low‐Na + medium.