Abstract
Spinorphin (LVVYPWT), an endogenous bioactive peptide purified from the spinal cord, demonstrates a nociceptive effect on bradykinin-induced pain in the rat and inhibitory activity against carrageenan-inducedneutrophil accumulation in the mouse model of acute inflammation. To further clarify its physiologicalrole in pain and inflammation, we quantified spinorphin in human cerebrospinal fluid (CSF) bycompetitive enzyme immunoassay (EIA) and analyzed the relation between its level and the physiological state. Levels of spinorphin measured in CSFs derived from patients with various types of pain other thancancer pain were higher in the pain group than in the controls (patients with pain-free and noninflammatory disease of the central nervous system) (21.4 ± 14.0 ng/ml, n=48 vs 8.61 ± 7.6 ng/ml, n=28, P<0.05). Furthermore, the activity of several spinorphin-processing enzymes that regulate some types of pain wasexamined. The activity of dipeptidyl peptidase III (DPPIII), an enkephalin-degrading enzyme, in CSFs ofthe pain group was lower than that in the control (l.40 ± 0.65 vs 2.05 ± 0.88 pmol / 30 min / 100 µl, P<0.05). Interestingly, a statistical moderate correlation was observed between the increase of spinorphin levels andthe decrease of DPPIII (r= -0.514, n=26). These results indicate that the level of spinorphin may, throughthe regulatory effect of enzymes, be an indicator of the pathophysiological state.
