Professor Han investigated the best settings to use for maximum production of the two central opioid peptides associated with pain relief.
In rat experiments he found that there was an approximately logarithmic relationship between frequency and opioid release:
- Enkephalin had maximum production at about 120 Hz
- Dynorphin had maximum production at about 2 Hz
Stimulation using both frequencies simultaneously had no different effect than using the high frequency only.
Shifting between low and high frequency stimulation for three seconds each (i.e. 2/100 stimulation) produced a simultaneous activation of the enkephalin and dynorphin systems, inducing a much more potent analgesic effect than that induced by a constant frequency stimulation.
‘Brain functions are regulated by chemical messengers that include neurotransmitters and neuropeptides. Recent studies have shown that acupuncture or electrical stimulation in specific frequencies applied to certain body sites can facilitate the release of specific neuropeptides in the CNS, elicitating profound physiological effects and even activating self-healing mechanisms. Investigation of the conditions controlling this neuro-biological reaction could have theoretical and clinical applications’ (Han, 2003).
Han, Ji-Sheng (2003) Acupuncture: neuropeptide release produced by electrical stimulation of
different frequencies. TRENDS in Neurosciences. J. 26:1, 17-22