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Expressions of preproenkephalin mRNA during electroacupuncture analgesia enhanced by fenfluramine
1State Key Laboratory of Medical Neurobiology, Shanghai Medical University, China.
Aim:
To study the changes of preproenkephalin (PPE) mRNA in rat brain in response to electroacupuncture (EA) combined with fenfluramine (Fen), a releaser of 5-HT.
Methods:
In situ hybridization histochemistry technique was used to observe the expression of PPE mRNA in rat brain during EA analgesia potentiated by Fen.
Results:
The greatest relative increase of PPE mRNA was seen in lumbar spinal cord (laminae I & II), nucleus raphe magnus, dorsal raphe nucleus, periaqueductal gray, interpeduncular nucleus, preoptic lateral area, amygdala nucleus and caudate-putamen (P < 0.01, vs NS + EA). Moderate increases were found in lateral septal, preoptic medial area, hypothalamus ventromedial nucleus, lumbar spinal laminae III & IV (P < 0.05, vs NS + EA). Thalamus showed no statistical significant change in PPE mRNA.
Conclusion:
The enhancing of PPE mRNA in relative brain nuclei is involved in potentiating action of Fen on EA.
Insights
Electroacupuncture (EA) combined with fenfluramine (Fen) significantly increases preproenkephalin (PPE) mRNA in key rat brain regions. This suggests enhanced opioid peptide expression contributes to Fen's potentiation of EA analgesia.
Area of Science:
- Neuroscience
- Molecular Biology
- Pharmacology
Background:
- Electroacupuncture (EA) is a therapeutic technique known for its analgesic effects.
- Fenfluramine (Fen) is a serotonin (5-HT) releasing agent that can potentiate EA analgesia.
- Preproenkephalin (PPE) is a precursor to endogenous opioid peptides involved in pain modulation.
Purpose of the Study:
- To investigate the effect of combining EA with Fen on the expression of PPE mRNA in the rat brain.
- To identify specific brain regions where PPE mRNA levels change in response to this combined treatment.
Main Methods:
- In situ hybridization histochemistry was employed to visualize and quantify PPE mRNA expression.
- The study focused on various brain regions, including the spinal cord, brainstem, and forebrain nuclei.
Main Results:
- A significant increase in PPE mRNA was observed in the lumbar spinal cord (laminae I & II), nucleus raphe magnus, dorsal raphe nucleus, periaqueductal gray, interpeduncular nucleus, lateral preoptic area, amygdala, and caudate-putamen (P < 0.01).
- Moderate increases in PPE mRNA were noted in the lateral septal area, medial preoptic area, ventromedial hypothalamus, and lumbar spinal cord laminae III & IV (P < 0.05).
- No significant changes in PPE mRNA expression were detected in the thalamus.
Conclusions:
- The observed enhancement of PPE mRNA in specific brain nuclei is a key mechanism underlying the potentiating effect of Fen on EA analgesia.
- These findings highlight the role of endogenous opioid systems in the synergistic action of EA and Fen.