[Inhibition of degranulation of human basophils by calcium antagonists]

The human basophil degranulation test (HBDT) quantifies the apparent disappearance of basophils after contact with the sensitizing allergen. The inhibition of degranulation by pharmacological products can be appreciated by incubating beforehand the basophils with the substance concerned during various times. The inhibitory effect is evaluated by the difference of degranulation with or without it. EDTA, sodium cromoglycate, verapamil and bepridil have been tested at different concentrations and at 3 times of basophils preincubation (0,15 and 30 minutes). Results obtained confirm previous reports concerning cromoglycate which didn't inhibit degranulation of basophils. EDTA at 3.4*10(-2)M and 3.4*10(-3)M concentration has an inhibitory effect, not increasing with the time of preincubation. The inhibition with verapamil is of the same order at 1*10(-4)M for the 3 times of incubation and weaker, but significant, at 1*10-M5 after 30 minutes of preincubation. Bepridil inhibits at 1*10(-4)M, but this effect disappears if basophils are preincubated 30 minutes with the drug. The inhibition of the specific basophil degranulation by these drugs is probably du to their calcium antagonist property. However their effect is not quite similar when cells are preincubated at different times with the drug. On the other hand, one can study with HBDT the inhibitory effect of a new product, even if the therapeutic indications would have to be studied afterwards.