ACTIONS AND CROSS-REACTIVITY OF ANTIALLERGIC AGENTS AND A CALCIUM-CHANNEL ANTAGONIST ON RAT PERITONEAL MAST-CELLS - DIFFERENCE IN THE ACTION MECHANISMS AND CROSS-REACTIVITY AMONG THE AGENTS

The actions of the antiallergic agents, disodium chromoglycate (DSCG), tranilast and ketotifen, and of a calcium channel antagonist, nicardipine, and cross-reactivity among the agents were examined by observing the inhibition of Ca-45 uptake and histamine release in rat mast cells stimulated by antigen and compound 48/80 (comp. 48/80). 1) All agents inhibited Ca-45 uptake and histamine release in mast cells stimulated by antigen. The inhibition of Ca-45 uptake by the antiallergic agents paralleled the inhibition of histamine release, while nicardipine inhibition of Ca-45 uptake was stronger than its inhibition of histamine release. 2) The action of DSCG on Ca-45 uptake and histamine release was significantly decreased in cells stimulated with antigen and phosphatidylserine (PS), while tranilast inhibition of histamine release was not affected by the addition of PS despite a significant decrease in the inhibition of Ca-45 uptake. 3) The inhibitory effect of DSCG and tranilast was significantly lower in mast cells stimulated by comp. 48/80 than in the cells stimulated by antigen. 4) Tachyphylaxis was observed in cells re-exposed to DSCG and tranilast following previous exposure to the agents. 5) Cross-reactivity was found between DSCG and tranilast.