It is mostly applied between the frequency of 50 to 120 Hz and it provides pain relief by increasing the gamma aminobutyric acid (GABA), endorphin, enkephalin, and dynorphin
levels in the spine.
In a study searching for the role of secretoneurin, it was demonstrated that local infusion of secretoneurin by microdialysis into the striatum and nigra led to increased release of glutamate, GABA and dynorphin
Han, "Decreased dynorphin
A (1-17) in the spinal cord of spastic rats after the compressive injury," Brain Research Bulletin, vol.
The CRH also releases another hormone, dynorphin
[73-75], which activates k opioid receptors (KORs) in the central and peripheral nervous system.
In turn, met-enkephalin, leu-enkephalin, [beta]-endorphin, [alpha]-neo-endorphin, dynorphin
, and nociceptin/orphanin are opioid peptides.
Delgado-Escueta," Altered patterns of dynorphin
immunoreactivity suggest mossy fiber reorganization in human hippocampal epilepsy," The Journal of Neuroscience, vol.
(37) also demonstrated increased levels of dynorphin
and enkephalin in the hippocampus and striatum of rats.
According to the current understanding there is a network of sex-steroid responsive neurons in the arcuate (infindubular) nucleus that coexpress Kisspeptin, NKB, Dynorphin
and ER[alpha] (KNDy or Kisspeptin neurons).
 Its ligand, the endogenous nociceptin/ orphanin FQ (N/OFQ) is 17 amino acid long and has resemblances with the endogenous ligand of the kappa opioid receptor dynorphin
. The anatomical distribution of NOP/ OFQ receptor ligand system has been observed in; cortex, amygdale, hippocampus, pontine nuclei, central gray, lateral septum, anterior olfactory nucleus, raphe complex, locus coeruleus, substantia nigra, interpeduncular nucleus, and the spinal cord,  therefore, clearly suggesting that nociceptin plays significant roles in the stress responses.
In addition to the development of excitatory inputs, the timing of puberty is influenced by a concomitant and gradual removal of prepubertal inhibitory inputs, such as [gamma] aminobutyric acid (GABA) and the opioid peptides [beta] endorphin and dynorphin
(Lehman et al.
Other ischemia-associated factors, such as arachidonic acid and lactate, endogenous polyamines, large dynorphin
, and nitric oxide, also exacerbate acidosis-mediated neuronal injury and ischemic damage [56, 63-65].
Eisenach, "Spinal cord dynorphin
expression increases, but does not drive microglial prostaglandin production or mechanical hypersensitivity after incisional surgery in rats," Pain, vol.