[Activity of DPP III in human cerebrospinal fluid derived from patients with pain].

Background: In the course of elucidating physiological roles of spinorphin, an endogenous regulator of enkephalin-degrading enzyme, we found that dipeptidyl peptidase III (DPP III) was contained in human cerebrospinal fluid (CSF). In this study, we examined the activity of DPP III in human CSF derived from patients with pain.

Methods: We used human CSF as specimen collected during operations under spinal anesthesia. Patients were divided into three groups, patients without pain (normal group), with acute pain, and with chronic pain. We measured DPP III activities in each group, using specific substrates, such as Arg-Arg-AMC.

Results: DPP III activity for human CSF in patients with acute pain was significantly lower compared with that in patients without pain (P < 0.05). Furthermore, DPP III activity correlated with APN activity, another spinorphin-degrading enzyme, in patients with pain (r = 0.444).

Conclusion: These results indicate that DPP III may play a role in regulation of endogenous opioids, leading to pain modulation.