engleski

Salivary Opiorphin Levels After Capsaicin Stimulation in Orofacial Pain Patients and Controls

Objectives: Opiorphin is an endogenous inhibitor of opioid degrading enzymes released by salivary glands and displaying strong analgesic properties. This study is aimed at comparing the intensity of burning pain sensation and salivary opiorphin levels after oral stimulation with capsaicin in burning mouth syndrome (BMS), chronic temporomandibular disorders (TMD) patients and healthy subjects. Methods: Forty subjects participated (8 BMS, 16 TMD-pain patients and 16 controls). Burning pain sensation was elicited by putting a series of 10 capsaicin-soaked disks (30µM) in contact with the dorsal tongue, and the intensity was recorded with a Numerical Pain Rating Scale (NPRS) every minute during a 5 minute application period and every 2 minutes during next 20 minutes upon termination of capsaicin stimulation. Saliva sampling for opiorphin levels was performed on three time points, before and twice following the stimulation. Opiorphin levels were quantified by HPLC-MS/MS. Analysis of variance (ANOVA), Repeated measurements ANOVA and post hoc-tests were used for data analysis. Results: The values of experimental burning pain sensation (peak values (at 5th measurement): controls =4.56±0.42 ; TMD=4.13±0.56 ; BMS=6.13±0.95) differed significantly between groups (p=0.0049), with significantly higher values in BMS group (BMS vs.TMD p=0.0052 ; BMS vs. controls p=0.0165). BMS patients showed statistically higher levels of opiorphin, compared to controls in second (BMS:3.47±1.18pg/ug ; control:0.90±0.19pg/ug ; p=0.035) and third sampling (BMS:4.58±1.84pg/ug ; control:0.90±0.15pg/ug ; p=0.014). Also, in BMS group, a statistically significant increase in opiorphin levels was observed between the 1st and 3rd sampling (p=0.0166). Conclusions: BMS patients experienced a more intense pain sensation after tongue stimulation by capsaicin than TMD patients and healthy control subjects. Opiorphin levels were higher in orofacial pain patients than in healthy subjects, and BMS patients displayed higher levels than TMD patients. These results indicate a specific regulation of opiorphin release in patients with oral painful conditions.

Opiorphin, Capsaicin, Saliva, Burning Mouth Syndrome, Temporomandibular Disorders

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