Prevention of anaphylactoid shock in the rat by the calmodulin antagonist thioridazine.

Calmodulin antagonists, which block intracellular calcium/calmodulin-dependent processes like exocytosis, inhibit effectively mast cell mediator release in vitro. Our experiments confirm that they are also effective in vivo. Thioridazine (5 mg/kg), a representative of the group, prevents the severe anaphylactoid shock in the rat, induced with compound 48/80, and permits a rapid and complete recovery, with special protection of respiration. Thus, calmodulin antagonists seem to be potential drugs for the management of mast cell-mediated allergic diseases.