• Journal of Oral Medicine and Pain
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• v.41 no.4
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• pp.195-199
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• 2016

Central sensitization represents a functional change of second order neuron induced by continuous deep pain input and maintained by psychosocial factors. When afferent neurons are involved with central sensitization, secondary hyperalgesia can appear. Secondary hyperalgesia is an increased sensitivity to stimulation without a local cause. Reports on secondary hyperalgesia to heat stimuli are relatively rare compared to mechanical stimuli. And there were few reports of secondary hyperalgesia to heat stimuli in the oral cavity. We presented a case of secondary hyperalgesia to heat stimuli in the gingival area induced by continuous odontogenic pain with a review of the related literature.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.4 no.1
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• pp.1-12
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• 2006

This study conducted RIII reflex measurement to examine degree of pain depending on polarity of high voltage pulsed current of primary and secondary hyperalgesia site in hyperalgesia rat by local thermal injury. Hind paw which was injury site was taken as primary hyperalgeisa site, sole which was injury adjacent site was taken as secondary hyperalgesia site, and mechanical pain threshold, thermal pain threshold and root mean square of RIII reflex were measured. This study was conducted with control group I of hyperalgesia rat at hind paw by thermal injury and experimental groups divided into cathodal high voltage treatment group II, anodal high voltage treatment group III and alternate high voltage treatment group IV, applied active electrode of high voltage pulsed current to hind paw directly, placed reference electrode on the sole of injury adjacent site and applied pulse frequency. It measured RIII reflex and obtained the following results: Root mean square of RIII reflex at primary hyperalgeisa site was significantly reduced in group II after 2 days of hyperalgesia. Group II showed significant decrease after 5 and 6 days of hyperalgesia. Root mean square of RIII reflex at secondary hyperalgesia site showed significant reduction in group II after 6 days of hyperalgesia. Consequently it was found that application of high voltage pulsed current of hyperalgesia site reduced RIII reflex at primary hyperalgeisa site and secondary hyperalgesia site by electrical stimuli. Effects by polarity of high voltage pulsed current showed the greatest reduction of pain threshold when cathodal active electrode was used.

• The Journal of Korean Physical Therapy
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• v.16 no.2
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• pp.181-194
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• 2004

The aim of this study was to investigate the effects of TENS and cold application on secondary thermal hyperalgesia in rats induced by muscle pain. Muscle pain was induced in male Sprague-Dowley rats by intra-muscular injection of gastrocnemius with $3\%$ carrageenan. The paw withdrawal latency(PWL) and tail flick test(TFT) to heat were used to detect secodary thermal hyperalgesia induced by the muscle pain. PWL and TFT were quantified before and 4, 10, and 24 h after induction of muscle pain and after application of TENS(100Hz, $100{\mu}s$, sensory intensity) and cold($4^{\circ}C$). TENS and cold significantly reduced the PWL and TFT to heat stimuli when compared with controls receiving no TENS and cold(p<.05). These results suggested that application of TENS and cold attributed to decrease secodary thermal hyperalgesia in rat induced by muscle pain.

• The Korean Journal of Pain
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• v.13 no.2
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• pp.164-174
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• 2000

Background: After an injury to tissue such as the skin, hyperalgesia develops. Hyperalgesia is characterized by an increase in the magnitude of pain evoked by noxious stimuli. It has been postulated that in the mechanism of hyperalgesia (especially secondary hyperalgesia) and allodynia, a sensitization of central nervous system such as spinal dorsal horn may contribute to development of hyperalgesia. However, the precise mechanism is still unclear. In the present study, we investigated the roles of N-methyl-D-aspartate (NMDA) receptor and nitric oxide (NO) system in the mechanism of hyperalgesia, and their relations with c-fos expression Methods: Inflammation was induced by injection of complete Freund adjuvant (CFA) into unilateral hindpaw of Sprague-Dawley rat. Behavioral studies measuring paw withdrawal responses by von Frey filaments and paw withdrawal latencies by radiant heat stimuli and stainings of nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase and c-fos immunoreactivity were performed. The effects of MK-801, an NMDA receptor blocker and $N^\omega$-nitro-L-arginine (L-NNA), a nitric oxide synthase (NOS) inhibitor were evaluated. Results: 1) Injection of CFA induced mechanical allodynia, mechanical hyperalgesia and thermal hyperalgesia. And it increased the number of NADPH-diaphorase positive neurons and c-fos expression neurons. 2) MK-801 inhibited mechanical hyperalgesia and thermal hyperalgesia induced by CFA and reduced the number of NADPH-diaphorase positive neurons and c-fos expression neurons. 3) L-NNA inhibited the thermal hyperalgesia and reduced the number of NADPH-diaphorase positive neurons, but did not affect the number of c-fos expression neurons. Conclusions: These results suggest that in the mechanism of mechanical hyperalgesia, NMDA receptor but not NO-system is involved and in the case of thermal hyperalgesia both NMDA receptor and NO system are involved. NO system did not affect the expression of c-fos, but c-fos expression and NOS activity were dependent on the activity of NMDA receptor.

• The Journal of Korean Physical Therapy
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• v.15 no.4
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• pp.190-198
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• 2003

Expression of c-fos, an immediate early gene, has accepted to be a marker of functional activity in neurons. This study was aimed to investigate the effects of cold therapy on the expression of spinal cord c-fos in rats of carrageenan-induced muscle pain. Muscle pain was induced in male Sprague-Dawley rats by intra-muscular injection of gastrocnemius with $2\%$ carrageenan. The paw withdrawal latency (PWL) and tail flick test (TFT) responses to heat stimuli were used to detect secondary hyperalgesia produced by the muscle pain and measured to assess the effects of cold. The expression of c-fos was determined in the lumbar regions of the spinal cord by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry assays. The secondary hyperalgesia to heat simuli (PWL and TFT) were significantly reduced in cold therapy compared with that in the controls. In RT-PCR assays the expression of c-fos mRNA was down-regulated in the lumbar spinal cord in cold group. In addition, Fos immunoreactivity in the dorsal horn of the lumbar spinal cord was decreased in cold group. These results suggested that application of cold attributed to increase PWL and TFT responses and to decrease expression of the c-fos produced by muscle pain.

• Journal of Oral Medicine and Pain
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• v.47 no.3
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• pp.126-134
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• 2022

Purpose: This study aimed to propose an efficient treatment approach for infection with different candida species. Methods: Fifty-three patients who presented with a chief complaint of oral mucosal pain and exhibited positive candida culture findings were divided into two groups (Candida albicans and non-albicans). Pain, mucosal manifestations, salivary flow rates, durations of disease and treatment, and responses to treatment (nystatin and clonazepam) were investigated in both groups. Results: Patients in the C. albicans group exhibited more prominent clinical characteristics (erythematous lesions, tongue coatings, and hyperalgesia) than those in the non-albicans group. In total, 70% of patients in the non-albicans group showed no abnormalities in the oral mucosa. Patients in the C. albicans group showed increased resistance to nystatin treatment compared to those in the non-albicans group, especially with longer disease durations. The patients resistant to nystatin treatment showed positive responses to clonazepam. Conclusions: Patients with oral mucosal pain should be tested for the presence of Candida, even in the absence of mucosal abnormalities, especially those infected with non-albicans species. If no response to antifungal therapy is observed, treatment with clonazepam should be initiated, especially in patients infected with C. albicans.