Morphine decreases early peritoneal innate immunity responses in Swiss-Webster and C57BL6/J mice through the inhibition of mast cell TNF-α release

Objective: To characterize immunosuppressive effects of morphine on the early innate immunity response of cytokine production in peritoneal cavity after LPS challenge. Methods: The effects of a single i.p. administration of morphine (3.1 or 31 mg/kg) on LPS-induced tumor necrosis factor alpha (TNF-alpha) and monocyte chemoattractant protein-1 (CCL2) intraperitoneal release was tested in Swiss-Webster, C57BL/6J, mast cell deficient Kit (Wsh/Wsh) (W-sh) and mast cell reconstituted (W-sh-rec) mice. Results: Morphine was found to inhibit LPS-induced TNF-alpha but not CCL2 release in the peritoneal cavity. Studies on mast cell deficient and reconstituted mice indicate that resident mast cells mediate selective morphine immunosuppression in the peritoneal cavity. (C) 2010 Elsevier B.V. All rights reserved.