Inhibitory action of verapamil and chlorpromazine on the release of slow-reacting substance of anaphylaxis from cat lung.

Verapamil, a calcium channel blocker, significantly inhibited the release of slow-reacting substance of anaphylaxis (SRS-A) from cat lung fragments challenged with either the calcium ionophore, A23187, or Ascaris extract. This effect was observed when verapamil was present at the concentrations of 10 microM and 50 microM. Chlorpromazine 10 microM significantly inhibited antigen-induced SRS-A release. Histamine release was low and no significant effect by verapamil or chlorpromazine could be shown.