Gene expression and localization of opioid peptides in immune cells of inflamed tissue: functional role in antinociception

Gene expression and localization of opioid peptides in immune cells of inflamed tissue: functional role in antinociception

Przewlocki R; Hassan AH; Lason W; Epplen C; Herz A; Stein C

Neuroscience

1992

Male; Pain Measurement; Analysis of Variance; Animals; Nucleic Acid Hybridization; Rats; Non-U.S. Gov't; Research Support; Biomarkers of Pain; RNA; Biomarkers Reference List; Inbred Strains; beta-Endorphin/genetics/metabolism; Calcitonin Gene-Related Peptide/analysis/metabolism; Endorphins/analysis/genetics/metabolism; Freund's Adjuvant; Gene Expression/radiation effects; Hindlimb; Inflammation/immunology/physiopathology; Messenger/genetics/metabolism; Nerve Fibers/physiology/ultrastructure; Oligonucleotide Probes; Pain/immunology/physiopathology; T-Lymphocytes/immunology/pathology; Whole-Body Irradiation

Our previous studies indicate that endogenous opioids (primarily beta-endorphin) released during stressful stimuli can interact with peripheral opioid receptors to inhibit nociception in inflamed tissue of rats. This study sought to localize opioid precursor mRNAs and opioid peptides deriving therefrom in inflamed tissue, identify opioid containing cells and demonstrate their functional significance in the inhibition of nociception. In rats with Freund's adjuvant-induced unilateral hindpaw inflammation we show that: (i) pro-opiomelanocortin and proenkephalin-mRNAs (but not prodynorphin mRNA) are abundant in cells of inflamed, but absent in non-inflamed tissue; (ii) numerous cells infiltrating the inflamed subcutaneous tissue are stained intensely with beta-endorphin and [Met]enkephalin (but only few scattered cells with dynorphin) antibodies; (iii) beta-endorphin is present in T- and B-lymphocytes, monocytes and macrophages; and (iv) whole-body irradiation suppresses stress-induced antinociception in the inflamed paw. Taken together, these data suggest that endogenous opioid peptides are synthesized and processed within various types of immune cells at the site of inflammation. Immunosuppression abolishes the intrinsic antinociception in inflammatory tissue confirming the functional significance of these cells.

1992

Article information provided for research and reference use only. PedPalASCNET does not hold any rights over the resource listed here. All rights are retained by the journal listed under publisher and/or the creator(s).

Journal Article

Backlog