Drug inhibition of ecto-ATPase and of phagocytosis in leukocytes.

Substituted phenothiazines and tricyclic antidepressants which inhibited the ecto-ATPase in leukocytes also markedly decreased the phagocytic activity of these cells. In affecting either the enzyme or phagocytosis the order of potency of the drugs was similar. Various other CNS drugs were ineffective. The results suggest possible involvement of ecto-ATPase in the phagocytic process, and indicate adverse effects of the aforelisted drugs on the host defense system against foreign materials, including microbes.