MU-opioid receptor-knockout mice: role of μ-opioid receptor in morphine mediated immune functions

doi:10.1016/S0169-328X(98)00212-5

Molecular Brain Research

Volume 61, Issues 1–2, 30 October 1998, Pages 190-194

https://doi.org/10.1016/S0169-328X(98)00212-5 Get rights and content

Abstract

The role of the μ-opioid receptor in immune function was investigated using μ-opioid receptor knockout mice (MOR-KO). Morphine modulation of several immune functions, including macrophage phagocytosis and macrophage secretion of TNF-α, was not observed in the MOR-KO animals, suggesting that these functions are mediated by the classical μ-opioid receptor. In contrast, morphine reduction of splenic and thymic cell number and mitogen-induced proliferation were unaffected in MOR-KO mice, as was morphine inhibition of IL-1 and IL-6 secretion by macrophages. These latter results are consistent with morphine action on a naloxone insensitive morphine receptor, a conclusion supported by previous studies characterizing a nonopioid morphine binding site on immune cells. Alternatively, morphine may act either directly or indirectly on these cells, by a mechanism mediated by either delta or kappa opioid receptors.

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Acknowledgements

This work was supported by NIH grants DA00564, DA01583, DA05695, K05-DA70554, F. and A. Stark Fund (MMF)-HHL and DA 08188 (SR).

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Citation Excerpt :
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Short communicationMU-opioid receptor-knockout mice: role of μ-opioid receptor in morphine mediated immune functions

Abstract

Section snippets

Acknowledgements

Eur. J. Pharm.

Neuropeptides

Immunology Letters

Immunopharmacology

Mol. Brain Res.

Cell. Immunol.

Biochem. Biophys. Res. Comm.