NEUROPEPTIDE-CONVERTING ENZYMES IN CEREBROSPINAL-FLUID - ACTIVITIES INCREASED IN PAIN FROM HERNIATED LUMBAR DISC, BUT NOT FROM COXARTHROSIS

We measured activities of dynorphin-converting enzyme (DCE), substance P endopeptidase (SPE) and angiotensin-converting enzyme (ACE) in cere brospinal fluid (CSF) in 13 patients with rhizopathic pain from an her niated lumbar disc, in 9 patients with pain from coxarthrosis and in 1 1 control patients without pain, In the patients with disc hernia and coxarthrosis, another sample of CSF was analyzed 3-12 months after tre atment, when pain had subsided. The DCE activity in the patients was h igher than that in both the control patients and the patients with pai n from coxarthrosis (nociceptive pain), Similarly, the activity of SPE was lower in the patients with herniated lumbar disc than in controls and in the patients with coxarthrosis. After treatment, the differenc e in activity compared to controls was lower, but still significant in patients with herniated discs. The ACE activity did not differ from c ontrols in patients with ischialgia, while it was increased in patient s with coxarthrosis. This increase also remained after arthroplasty wi th pain relief. In conclusion, measurements of neuropeptides may be us eful for evaluating neuropathic pain.