• The Journal of Korean Medicine
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• v.24 no.3
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• pp.108-117
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• 2003

Objective : The central opioid mechanism of acupuncture analgesia has been fairly well documented in acute behavioral experiments, but little electrophysiological study has been performed on the peripheral mechanism and subtypes of opioid receptors responsible for acupuncture-induced antinociception in chronic animal models. In the present electrophysiological experiment, we studied the peripheral mechanism and opioid receptor subtypes which Were implicated in electroacupuncture-induced antinociception in the rat with chronic inflammatory and neurogenic pain. Methods : In the rat with complete Freund's adjuvant-induced inflammation and spinal nerve injury, dorsal horn cell responses to afferent C fiber stimulation were recorded before and after electroacupuncture (EA) stimulation applied to the contralateral Zusanli point for 30 minutes. Also studied Were the effects of specific opioid receptor antagonists and naloxone methiodide, which can not cross the blood-brain barrier, on EA-induced inhibitory action. Results : EA-induced inhibitory action was significantly attenuated by naloxone methiodide, suggesting that EA-induced inhibition was mediated through peripheral mechanism. Pretreatment, but not posttreatment of naltrexone and spinal application significantly blocked EA-induced inhibitory actions. In inflammatory and neurogenic pain models, ${\mu}-$ and ${\delta}-opioid$ receptor antagonists (${\beta}-funaltrexamine$ & naltrindole) significantly reduced EA-induced inhibitory action, but ${\kappa}-opioid$ receptor antagonist had weak inhibitory effect on EA-induced antinociception. Conclusion : These results suggest that 2Hz EA-stimulation induced antinoeiceptive action is mediated through peripheral as well as central mechanism, and mainly through ${\mu}-$ and ${\delta}-opioid$ receptors.

• Parasites, Hosts and Diseases
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• v.60 no.4
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• pp.247-254
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• 2022

Vincristine (VCR) is a chemotherapeutic agent widely used in treatment of malignancies. However, VCR has a limitation in use since it commonly causes a painful neuropathy (VCR-induced peripheral neuropathy, VIPN). Inflammatory cytokines secreted by immune cells such as macrophages can exacerbate allodynia and hyperalgesia, because inhibiting the inflammatory response is a treatment target for VIPN. In this study, we investigated whether Trichinella spiralis, a widely studied helminth for its immunomodulatory abilities, can alleviate VCR-induced allodynia. Von Frey test showed that T. spiralis infection improved mechanical allodynia at 10 days after VCR injection. We further observed whether the difference was due to mitigated axon degeneration, but no significant difference between the groups in axonal degeneration in sciatic nerves and intra-epidermal nerve fibers was found. Conversely, we observed that number of infiltrated macrophages was decreased in the sciatic nerves of the T. spiralis infected mice. Moreover, treatment of T. spiralis excretory-secretory products caused peritoneal macrophages to secrete decreased level of IL-1β. This study suggests that T. spiralis can relieve VCR-induced mechanical allodynia by suppressing neuroinflammation and that application of controllable degree of helminth may prove beneficial for VIPN treatment.

• Journal of Life Science
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• v.27 no.5
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• pp.600-610
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• 2017

It was common that the classification of itching was classified into four categories according to the neurophysiological mechanisms of pruritoceptive itching, neuropathic itching, neurogenic itching and psychogenic itching. Recently it was classified by clinical criteria. The neurotransmission pathway of itch is divided into histamine-dependent pathway and histamine-independent pathway. Different receptors and neuropeptides act on each itch mediator. Itch mediators such as histamine, BAM8-22, and chloroquine are transmitted through the histamine-dependent pathway. Cowhage spicule, protease, and TSLP (Thymic stromal lymphopoietin) have been reported to be related to the histamine-independent pathway. These itch mediators, receptors, and neuropeptides are the targets of treatment for itching. Although itching and pain are typical noxious stimuli, and in the past, it was argued that two senses were transmitted through one noxious stimulus receptor. It has recently been shown that itching and pain have an independent neurotransmitter system and both neuronal systems inhibit each other. In addition, the mutual antagonism between itching and pain is explained by various mechanisms. Recently, many new mediators and receptors are being studied. The studies on histamine 4 receptor (H4 receptor) have been actively conducted. And the H4 receptors are expressed in immune cells such as T cells. The therapeutic agent for blocking the H4 receptor can inhibit the inflammatory reaction itself, which is important for the itching and chronicization. Understanding the underlying mechanisms of itching and studying new itch mediators will lead to the development of effective therapies, and this is what I think the itching study will go on.

• Journal of Acupuncture Research
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• v.19 no.4
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• pp.167-182
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• 2002

This experiment was designed to investigate the effects of electroacupuncture (EA) on chronic pains and factors that affected EA effects. The responses of wide dynamic range (WDR) cells to electrical stimulation of $A{\delta}$ & C afferent fibers were used as an index of pain in rats with chronic pains induced by intraplantar injection of complete Freund's adjuvant or peripheral nerve injury. In rats with chronic pains, low (2Hz) and high (100Hz) frequency EA stimulation applied to zusanli caused the inhibition of WDR cell responses in about 60% of rats and the inhibitory actions were dependent on the stimulus strength. EA stimulation also induced an excitation of WDR cell responses in 23.9% of rats and no effect in 15.8% of rats. However, it seemed that in normal rats compared to the rat with chronic pains, the incidence of which EA stimulation caused the excitation or no effect was high. Reversible spinalization almost completely blocked EA-induced inhibitory or excitatory effects. EA stimulation more frequently induced the excitation of WDR cell responses in lightly anesthetized (0.6%) rats and the enhanced responses of WDR cells were inhibited by EA stimulation in the rat anesthetized with 1.5% enflurane. These experimental findings suggest that in rats with chronic pain, EA stimulation inhibited WDR cell responses to slow $A{\delta}$ and C fiber stimulation and EA-induced inhibitory action was under the control of descending inhibitory system and degree of anesthesia.

• The korean journal of orthodontics
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• v.29 no.1 s.72
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• pp.73-81
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• 1999

Midpalatal suture expansion is often used for patients haying narrow maxillary arch, cleft palate, respiratory handicap with narrow nasal cavity. CGRP has been known as a modulator of pain transmission in central nervous system and a local effector to peripheral tissue causing vasodilation, increase of blood flow, modulation of immune system, regulation of macrophagic function and stimulation of bone formation. To investigate changes of CGRP-immunoreactive nerve fibers in midpalatal suture during the expansion, immunohistochemical study was performed by using rats. Experimental rats (10 weeks, 250 gm) were divided into five groups (control, 1, 4, 7, 14 days group (each n=4) and applied orthodontic force (approximately 200gm) to upper anterior incisors. Frozen sections of midpalatal suture area were immunostained by using rabbit antisera. The results were as follows. ${\cdot}$ The CGRP-immunoreactive nerve fibers were hardly observed in control group. ${\cdot}$ In 1 day group, the CGRP-immunoreactive nerve fibers were more increased around the vessels than control group. ${\cdot}$ In 4 days group, the CGRP-immunoreactive nerve fibers were more increased than control group, but not more increased than 1 day group. Vascular diameter was more enlarged. ${\cdot}$ In 7 days group, especially, hematoxilin affinity of cells was remarkable and cells were arranged along the bone margin. The CGRP-immunoreactive nerve fibers were more reduced than 4 days group and vascular diameter was also reduced. ${\cdot}$ In 14 days group, the CGRP-immunoreactive nerve fibers were similar to those of 7 days group and the irregularity of bone margin was almost recoverd. In Conclusion, the CGRP-immunoreactive nerve fibers nay be related to initial neurogenic inflammatory reaction in expanding mid-palatal suture.