HYPEROSMOLAR INDUCED HISTAMINE-RELEASE FROM MAST-CELLS - A MECHANISM FOR THE PATHOGENESIS OF EXERCISE-INDUCED ASTHMA

Hyperosmolar buffer solutions produced by the addition of mannitol (0. 1-1.0 M) induced histamine release from mast cells from dispersed huma n lung (DL), bronchoalveolar lavage (BAL) and the rat peritoneal cavit y (RPMC). The maximal releases were ca 60% (RPMC), 40% (BAL) and 15% ( DL), respectively. Under defined conditions, the release from the RPMC was shown to be non-cytotoxic with biphasic kinetics. The process was inhibited by disodium cromoglycate, nedocromil sodium and theophyllin e, with IC50 values of ca 100 muM, 100 muM and greater than 10 mM, res pectively. On the basis of these results, the role of hyperosmolar ind uced mast cell activation in exercise-induced asthma is discussed.