Enhanced prostaglandin E2 and thromboxane B2 release from resident peritoneal macrophages isolated from morphine-dependent rats.

Resident peritoneal macrophages from morphine-addicted rats (4 days) released more prostaglandin (PG) E2 and thromboxane (Tx) B2, but not 6-keto-PGF1 alpha, than cells from control animals. This effect, which was due to an enhancement of endogenous AA turnover, was not related to any changes in cAMP synthesis or lysosomal enzyme secretion. [D-Ala2]-Met-enkephalin had no effect on eicosanoid release in vitro. Both morphine and PGE2 have been shown to depress macrophage functions. We suggest that morphine-stimulated macrophage PGE2 synthesis, and the consequent inhibition of phagocytosis, could contribute to the decreased resistance to infections associated with opiate addiction.