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Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Actions of endotoxin and morphine
1Department of Biology, Seton Hall University, South Orange, NJ 07079, USA. changsul@shu.edu
Advances in Experimental Medicine and Biology
|December 1, 2001
Summary
Bacterial endotoxins, like lipopolysaccharide (LPS), increase mu opioid receptors. This interaction with morphine may negatively impact immune responses and cell viability, suggesting a complex interplay in pathological conditions.
Area of Science:
- Neuroimmunology
- Endocrinology
- Pharmacology
Background:
- Opioid receptors play a role in physiological responses.
- Endotoxins, such as lipopolysaccharide (LPS), trigger significant immune reactions.
- Cytokines are implicated in modulating receptor expression during inflammation.
Purpose of the Study:
- To investigate the effect of lipopolysaccharide (LPS) on mu opioid receptor expression.
- To determine the impact of morphine on endothelial cells and inflammatory responses.
- To explore the interaction between endotoxins and opioid pathways in pathological conditions.
Main Methods:
- Treatment of rat mesentery with LPS to assess mu opioid receptor induction.
- Culturing human brain microvascular endothelial cells (HBMEC) to study morphine effects.
- Assessing endothelial cell permeability and viability in response to morphine and LPS.
- Measuring IL-1beta secretion from HL-60 cells.
Main Results:
- LPS treatment induced mu opioid receptor expression in rat mesentery, potentially mediated by IL-1.
- Morphine increased endothelial cell permeability and decreased viability, and potentiated LPS effects.
- Morphine pre-treatment enhanced LPS-induced IL-1beta secretion.
- Data suggest a positive feedback interaction between LPS and morphine.
Conclusions:
- Endotoxin exposure, particularly LPS, can induce mu opioid receptors, influencing opioid-dependent pathways.
- Morphine may adversely potentiate endotoxin effects, leading to detrimental outcomes.
- These findings highlight a significant interaction between endotoxins and opioids with potential clinical implications for immune modulation.
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