| Co-Investigator(Kenkyū-buntansha) |
OHKUBO Tsuyako Fukuoka Dental College, Department of Pharmacology, Assistant, 歯学部, 助手 (40099065)
SHIBATA Manabu Fukuoka Dental College, Department of Pharmacology, Lecturer, 歯学部, 講師 (40099049)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1992: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1991: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
Neurogenic inflammation, which involves the release of neuropeptides from capsaicin-sensitive sensory nerves, may contribute to inflammatory diseases in tissues such as skin, airways and gut. We had confirmed the existense of substance P (SP)- containing fibers in rat dental pulp, and have suggested that pulpitis may also be neurogenic inflammatory diseases. Capsaicin has been known as a releaser and depletor of SP, and phenolic compounds partly resemble capsaicin in chemical structure. Thus, the present study investigated the effects of eugenol (EG), guaiacol (GC) and thymol (TM) on analgesic action, blood flow and SP release in comparison with capsaicin, and the results were as follows : 1) Pain sensitivity was measured in three ways (heat, pressure and chemical stimuli), and the order of potency for analgesia was EG>HC>TM when these were administered intrathecally in mice, but was weaker than that of capsaicin. 2) EG increased cutaneous blood flow which was measured with a laser Doppler devise in rat hindpaw, and this was antagonized by spantide (an SP antagonist), in the same manner as capsaicin. 3) Rat mandibular incisor pulps were desected out and chopped, and slices weighing about 110 mg were transfered to superfusion chamber. SP release from slices of pulp was increased by EG and GC, but was less than by capsaicin. SP release from slices of rat spinal cord by EG and GC was equal to the potency of capsaicin.
These results suggest that phenol analogues such as EG and GC may have a neurotoxic action which releases and depletes SP from small diameter sensory fibers like capsaicin, and may cause analgesic and anti-inflammatory effect. Furthermore, it is possible that capsaicin will be able to use as analgesics for dental practice.
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