Influence of electro-acupuncture on pain threshold in horses and its mode of action

Electro-acupuncture (EA) treatments varied in their effect on pain threshold in horses. EA stimulation using local acupuncture points or/and high frequency (80–120 Hz) can be more effective to relieve the experimental pain than the use of distal points and/or low frequency (20 Hz). The acupoints close to the painful areas may need to be stimulated with high frequency EA while the acupoints far from the painful areas may be stimulated with low frequency EA. The release of β-endorphin may be one of the pathways in which electro-acupuncture relieves the experimental pain.