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Participation by opioids in the immunostimulatory activity of myelopeptides
L A Zakharova1, R G Belevskaya, O G Yanovskii
1Shemyakin Institute of Bioorganic Chemistry, Academy of Sciences of the USSR, Moscow.
Abstract:
Bone marrow myelopeptides (MP), besides having immunostimulatory activity, had a pronounced dose-dependent effect on the development of pain sensitivity in mice. Nanogram amounts of MP evoked a hyperalgesic response and increased antibody formation to sheep red blood cells three to nine times. Milligram amounts of MP had a hypoalgesic effect and did not affect antibody response. Opioid peptides derived from the bone marrow MP are involved in the expression of the antibody response, and a mixture of synthetic opioids, corresponding in composition to that found in natural MP, stimulated antibody production. The antibody-stimulating effect of MP was abolished by naloxone. Of the opioid peptides, only beta-endorphin showed antibody-stimulating activity. On reversed-phase chromatography the antibody-stimulating peptides and beta-endorphin were eluted in different fractions, indicating that the immunostimulatory and opioid activities are produced by different peptide molecules.
Insights
Bone marrow myelopeptides (MP) exhibit dual effects on pain sensitivity and immune response in mice. Low doses of MP increase pain and antibody formation, while high doses decrease pain, suggesting distinct molecular mechanisms.
Area of Science:
- Immunology
- Neuroscience
- Pharmacology
Background:
- Bone marrow myelopeptides (MP) are known to possess immunostimulatory properties.
- The role of MP in modulating pain sensitivity and immune responses requires further elucidation.
Purpose of the Study:
- To investigate the dose-dependent effects of bone marrow myelopeptides (MP) on pain sensitivity and antibody formation in mice.
- To explore the involvement of opioid peptides in the immunostimulatory activity of MP.
Main Methods:
- Administration of varying doses of MP to mice to assess pain sensitivity and antibody production against sheep red blood cells.
- Utilizing naloxone to block opioid receptors and investigate the role of endogenous opioids.
- Employing reversed-phase chromatography to separate and analyze peptide components of MP.
Main Results:
- Nanogram doses of MP induced hyperalgesia and significantly increased antibody formation.
- Milligram doses of MP resulted in hypoalgesia with no effect on antibody response.
- The antibody-stimulating effect of MP was inhibited by naloxone, and beta-endorphin was identified as a key antibody-stimulating opioid peptide.
Conclusions:
- Bone marrow myelopeptides (MP) exert dose-dependent effects on pain sensitivity and immune responses.
- Opioid peptides within MP are involved in modulating antibody production, with beta-endorphin playing a significant role.
- Immunostimulatory and opioid activities of MP are mediated by distinct peptide molecules.