Abstract
1) The mast cells isolated from the peritoneal fluid of rats are easily degranulated, following the incubation with either a-chymotrypsin (10-300γ/ml), sinomenine (3-100γ/ml), dextran (100-1, 500γ/ml) or compound 48/80 (0.1-1.0γ/ml). The activity is approximately equal to α-chymotrypsin in a concentration of 300γ/ml, sinomenine in that of 100γ/ml and compound 48/80 in that of 0.5γ/ml and somewhat weaker in 1, 500γ/ml of dextran.
2) Addition of glucose in a concentration of 0.1 per cent to the above described system hardly ameliorates the degranulation effect.
3) Preincubation of the mast cells with either diphenhydramine (10-1, 000γ/ml), cyproheptadine (1-100γ/ml), homochlorcyclizine (1-100γ/ml) or dexamethasone (0.1-10γ/ml) antagonizes the effect induced by the histamine liberators. The activity of cyproheptadine, homochlorcyclizine and dexamethasone is approximately the same in potency, while that of diphenhydramine is somewhat weaker than that of the others.
