[Kyotorphin like substance in human cerebrospinal fluid of patients with persistent pain].

Kyotorphin is an analgesic neuropeptide isolated from the bovine brain in 1979. Further studies showed that kyotorphin produces an analgesia through an increased release of met-enkephalin in the brain and the spinal cord. We showed that it is also found in the human cerebrospinal fluid and the concentrations of kyotorphin in normal human CSF is 1.19 +/- 0.51 pmol.ml-1. We also found that it is lower in patients with persistent pain (0.24 +/- 0.04 pmol.ml-1). Above results suggest that kyotorphin acts as a putative neuromediator and/or an endogenous pain modulator in the human brain.