J Neurogastroenterol Motil.  2010 Jul;16(3):306-314.

Effect of Electroacupuncture on Visceral Hyperalgesia, Serotonin and Fos Expression in an Animal Model of Irritable Bowel Syndrome

• Wu JC
• Ziea ET
• Lao L
• Lam EF
• Chan CS
• Liang AY
• Chu SL
• Yew DT
• Berman BM
• Sung JJ

Abstract

BACKGROUND/AIMS
While it is well established that acupuncture relieves somatic pain, its therapeutic effect on visceral pain such as irritable bowel syndrome (IBS) is unclear. We evaluated the effect of acupuncture in treating visceral hyperalgesia in an animal model.
METHODS
Sprague-Dawley rats (n = 8 per group) with prior neonatal maternal separation stress were randomly allocated to receive 3-day treatment of either electroacupuncture (EA) or sham acupuncture at acupoint ST-36. Another group of rats without prior maternal separation was included as non-handled controls. Colorectal distension was performed on the day after acupuncture treatment. The 3 groups were compared for pain threshold as determined by abdominal withdrawal reflex and visceromotor response as measured by electromyogram. Colon, spinal cord, and brainstem were sampled for topographic distribution and quantitative assessment of serotonin and Fos expression by immunohistochemistry.
RESULTS
Rats in EA group had significantly higher pain threshold compared to those in sham acpuncture group (25.0 +/- 5.7 mmHg vs 18.7 +/- 5.2 mmHg, p = 0.01) and it was comparable with that of non-handled treatment naive controls (29.4 +/- 9.3 mmHg, p = 0.28). They also had lower visceromotor response as measured by electromyogram compared to those received sham acupuncture at all colorectal distension pressures. EA significantly suppressed Fos expression in doral raphe nuclei of brainstem, superficial dorsal horn of spinal cord and colonic epithelium but suppressed 5-HT expression only in brainstem and spinal cord.
CONCLUSIONS
Electro acupuncture attenuates visceral hyperlagesia through down-regulation of central serotonergic activities in the brain-gut axis.

Keyword

Electroacupuncture; Hyperalgesia; Brain-gut axis; Fos; Serotonin

MeSH Terms

Acupuncture
Acupuncture Points
Animals
Axis, Cervical Vertebra
Benzodiazepines
Brain Stem
Colon
Down-Regulation
Electroacupuncture
Epithelium
Horns
Hyperalgesia
Immunohistochemistry
Irritable Bowel Syndrome
Models, Animal
Nociceptive Pain
Pain Threshold
Raphe Nuclei
Rats
Rats, Sprague-Dawley
Reflex
Salicylamides
Serotonin
Spinal Cord
Visceral Pain
Benzodiazepines
Salicylamides
Serotonin