PT - JOURNAL ARTICLE AU - D M Ritchie AU - J N Sierchio AU - C M Bishop AU - C C Hedli AU - S L Levinson AU - R J Capetola TI - Evaluation of calcium entry blockers in several models of immediate hypersensitivity. DP - 1984 Jun 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 690--695 VI - 229 IP - 3 4099 - http://jpet.aspetjournals.org/content/229/3/690.short 4100 - http://jpet.aspetjournals.org/content/229/3/690.full SO - J Pharmacol Exp Ther1984 Jun 01; 229 AB - Several calcium-entry blockers, i.e., verapamil, nifedipine, flunarizine and diltiazem, were evaluated for their effects in models of immediate hypersensitivity disease. Verapamil, flunarizine and diltiazem were all effective in inhibiting antigen-induced bronchospasm in the guinea pig; however, the effects seen were at relatively high doses compared to the doses known to cause cardiovascular effects. Nifedipine caused no significant inhibition of resistance or compliance changes induced by antigen. Flunarizine, verapamil and diltiazem were ineffective in inhibiting antigen-induced histamine release from rat peritoneal mast cells in vitro. Although these compounds were active inhibitors of 5-D-[5,6,8,9,H,12,14,15-3H(N)]-hydroxy-6,8,11,14-eicosatetraenoic acid production in rat basophilic leukemia-1 cells, only flunarizine and verapamil showed effects on the 5-lipoxygenase enzyme when assayed directly. Also, these compounds were ineffective on SRS-A mediated bronchospasm in vivo. These data suggest that the currently available calcium entry blockers have little potential use in immediate hypersensitivity reactions.