Han J S, Chen X H, Sun S L, Xu X J, Yuan Y, Yan S C, Hao J X, Terenius L
Department of Physiology, School of Basic Medical Sciences, Beijing Medical University, Beijing People's Rep. China Department of Orthopedics, The First University Hospital, Beijing Medical University, Beijing People's Rep. China Department of Anesthesiology, Xuan-Wu Hospital, Beijing People's Rep. China Department of Drug Dependence Research, Karolinska Institute, 104 01 Stockholm Sweden.
Pain. 1991 Dec;47(3):295-298. doi: 10.1016/0304-3959(91)90218-M.
Transcutaneous nerve stimulation (TENS) treatment was given for 30 min to 37 patients divided into 3 groups of 10 patients and 1 group of 7 patients. Two groups received low-frequency (2 Hz) and the other 2 groups high-frequency (100 Hz) stimulation. A diagnostic lumbar cerebrospinal fluid (CSF) sample was obtained immediately before and after stimulation. The CSF samples were subjected to analysis of immunoreactive (ir) opioid peptides, Met-enkephalin-Arg-Phe (MEAP) from preproenkephalin and dynorphin A (Dyn A) from preprodynorphin, respectively. Low frequency TENS applied on the hand and the leg resulted in a marked increase (367%, P less than 0.05) of ir-MEAP but not ir-Dyn A, whereas high-frequency (100 Hz) TENS produced a 49% increase in ir-Dyn A (P less than 0.01) but not ir-MEAP. This is the first report in humans that 2 Hz and 100 Hz peripheral stimulation induces differential release of peptides from preproenkephalin and preprodynorphin, respectively.