著者

櫻井 博紀 佐藤 純一 青野 修一 新井 健一 井上 真輔 西原 真理 畠山 登 尾張 慶子 西須 大徳 牧野 泉 牛田 享宏

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.34, no.4, pp.336-341, 2019-12-20 (Released:2020-03-14)

参考文献数

19

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Patients who complain of chronic pain have various symptoms and complicated pathologies, and there are often cases in which the symptoms worsen due to weather changes. However, few studies have examined the nature of pain affected by weather changes. In this time, we investigated the characteristics of patients with weather–related pain. As results, their pain intensity is moderate and they can maintain moderate daily activity. But in psychosocial factors, they have low self–efficacy and high catastrophic thinking. As treatment for chronic pain, exercise therapy managed by a therapist is highly recommended in non–drug therapy. Patients with weather–related pain often complain at head and neck shoulders. Evidences on the effects of exercise therapy for these body parts have also been reported. We hope that capturing the characteristics of patients with weather–related pain will lead to more appropriate treatments tailored to the pathological condition of the patients.

著者

上田 豊

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.32, no.4, pp.272-279, 2017-12-20 (Released:2018-05-31)

参考文献数

11

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In Japan, cervical cancer tends to develop at a younger age. Cervical cancer screening rate in Japanese females is extremely low among developed countries. Therefore, HPV vaccine was expected to prevent cervical cancer effectively in Japan. An urgent promotion project for HPV vaccination was initiated by the Ministry of Health, Labour and Welfare (MHLW) in 2010. From April 2013, periodical vaccination of 12 to 16–year–old was initiated. However, so–called serious adverse events upon HPV vaccinations was repeated­ly reported in the media and the MHLW announced suspension of the recommendation of HPV vaccination in June 2013. Consequently, the inoculation rate has sharply declined, and a unprotected group against HPV will result in higher incidences of HPV infection and cervical cancer. It is necessary for us to face the increased risk of HPV infection and cervical cancer for girls who have refrained from HPV vaccination.

著者

木口 倫一 岸岡 史郎

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.29, no.1, pp.9-16, 2014-03-10 (Released:2014-03-29)

参考文献数

21

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Recently, the involvement of inflammatory mediators such as chemokines in neuropathic pain has been focused. Among inflammatory cells recruited into the injured peripheral nerves, macrophages play key roles in chronic neuroinflammation through cytokine–chemokine network. As epigenetic histone modifications induce long–lasting expression of inflammatory mediators, we highlight the contribution of histone modifications in the injured peripheral nerves to neuropathic pain.   After partial sciatic nerve ligation (PSL) in mice, F4⁄80+ macrophages were accumulated in the injured sciatic nerve (SCN). By microarray analysis, several inflammatory chemokine ligands and those receptors were upregulated in the injured SCN on day 7 after PSL. Indeed, the expression levels of CC–chemokine ligand (CCL) 3 and CCL8 showed the highest upregulation, and were confirmed by quantitative RT–PCR. Moreover, those receptors including CCR1, CCR2 and CCR5 were markedly upregulated after PSL. Chromatin precipitation assay revealed the acetylation in K9 residue (H3K9Ac) and trimethylation in K4 residue (H3K4me3) of histone H3, facilitating gene transcriptions associated with chromatin remodeling, on the promoter regions of CCLs in the injured SCN. By immunohistochemistry, upregulated CCL3 or CCL8 was located on the accumulated F4⁄80+ macrophages. Expressions of H3K9Ac and H3K4me3 were also increased in the injured SCN, and those were detected in the nuclei of macrophages expressing CCLs.   These findings indicate that facilitation of chemokine signaling through histone H3 modifications in macrophages largely contributes to peripheral neuroinflammation leading to neuropathic pain. Further research considering the critical components of peripheral neuroinflammation exploit novel therapeutic strategy of neuropathic pain.

著者

平川 善之 原 道也 藤原 明 花田 弘文 森岡 周

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.28, no.1, pp.23-32, 2013-03-10 (Released:2013-04-04)

参考文献数

29

被引用文献数

2

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Total knee arthroplasty (TKA) is a surgical treatment for conditions such as knee osteoarthritis; the treatment aims to relieve knee pain and improve quality of life. Treatment outcomes are stable; however, it has been reported that postoperative pain becomes chronic in 15 - 20% of cases. The aim of this study was to examine the factors involved in the chronicity of postoperative pain by investigating the effects of cognitive and psychological factors on postoperative pain at 3 weeks, 5 weeks, and 4 months post-operation. Subjects were 50 patients who underwent TKA (8 men and 42 women, mean age: 74.8 ± 6.5 years). Cognitive factors in this study comprised an assessment of neglect-like symptoms; such symptoms included decreased “cognitive function regarding the existence of one's own limbs" or “cognitive function regarding the motion perception of one's own limbs." The severity of these symptoms was assessed using the method described by Galar et al. Psychological factors comprised assessments of anxiety and catastrophic thinking about pain. Anxiety was assessed using the state-trait anxiety inventory, while catastrophic thinking about pain was assessed using the pain catastrophizing scale (comprises categories of helplessness, magnification, and rumination). Postoperative pain was assessed using a visual analog scale (VAS). Multiple regression analysis by using VAS as the dependent variable and all other factors as independent variables showed the following factors to be significantly correlated with VAS: neglect-like symptoms at 3 weeks, 5 weeks, and 4 months post-operation and rumination at 3 weeks and 4 months post-operation. Sensory integration becomes difficult because of decreased sensory function in neglect-like symptoms; this is thought to be caused by body image becoming inaccurate. On the basis of these findings, it is considered necessary to approach for the improvement of sensory function in postoperative rehabilitation. In addition, rumination is persistent in pain, which is believed to result in a prognosis of a psychological state of severe anxiety. Therefore, methods for dealing with postoperative pain and giving patients a prognosis that is as precise as possible are thought to be necessary. These measures are thought to be factors in relieving postoperative pain and preventing it from becoming chronic.

著者

藤巻 高光 桐野 高明

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.15, no.2, pp.57-61, 2000-07-31 (Released:2014-06-19)

著者

池田 亮

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.30, no.4, pp.208-215, 2015-12-10 (Released:2016-01-06)

参考文献数

38

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The sense of light touch is indispensable for environmental exploration,social interaction, and skilled tasks but the underlying mechanisms are largely unknown in mammals. Tactile dysfunction such as neuropathic pain produce allodynia which is grievous pain generated by light touch. This intra ctable phenomenon is induced by neural sensitization after the damage to nervous system. Along with the nervous system mechanisms, mechano transdcution in the tactile end organs play a crucial role to form mechanical allodynia. Thus, the elucidation of touch mystery is great expected matter to develop the effective treatment against mechanical allodynia. Merkel discs are one of the tactile special end organs thought as putative mechanoreceptors in the skins and can make sophisticated discrimination. We performed in situ patch–clamp recording from Merkel cells which compose Merkel discs in company with Aβ–afferent nerve endings. As a result, Merkel cells showed transduction of tactile stimuli via “Piezo2” channels and encode tactile signals in the form of Ca2+ action potentials. Recent advances using conditional knock out mice also show the same molecular mechanisms for Merkel cells mechanotransduction. These findings provide new insights into how to achieve delicate tactile sensation and may have clinical therapeutic implications.

著者

栁澤 琢史

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.36, no.1, pp.35-41, 2021-04-30 (Released:2021-06-18)

参考文献数

27

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Phantom limb pain is an intractable pain for which no effective treatment has been establish­ed. The pain has been attributed to abnormal plastic changes in the sensory motor cortex corresponding to the deafferented body part. Some feedback therapy such as mirror therapy have been applied to modify the abnormal cortical changes, although it is not been unveiled how to change the corresponding sensory motor cortex to reduce pain.We have applied neural decoding to magnetoencephalography (MEG) to extract motor information of the upper limb, and realized a Brain–Computer Interface (BCI) that allows patients to operate a prosthetic hand as if they were moving a phantom limb. In addition, we have demonstrated that neurofeedback (NF) training to control the BCI induced plastic changes in the patient’s sensorimotor cortex and changes in the pain. Actually, the training to attenuate the motor representation of the phantom limb reduced the pain.In addition, we evaluated the efficacy of the NF training by a blinded crossover trial of training with three consecutive days. Twelve patients were trained to control the phantom limb images, that were controlled through BCI. After three days NF trainings, the pain assessed with the Visual Analogue Scale (VAS) was significantly reduced for five days. Furthermore, the pain reduction was associated with the attenuation of the motor representation of phantom limb. These results suggest that the residual motor representations of phantom limb cause the phantom limb pain.We have demonstrated that the NF training elucidates the pathogenesis of chronic pain and develops a new treatment.

著者

松下 晋大 藤田 亜美 水田 恒太郎 大坪 瀬奈 蒋 昌宇 上村 裕平 小杉 寿文 熊本 栄一

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.28, no.1, pp.9-21, 2013-03-10 (Released:2013-04-04)

参考文献数

24

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Traditional Japanese medicine (Kampo medicine) is known to have a variety of pharmacological actions including antinociception. We have recently revealed that transient receptor potential (TRP) channel agonists such as capsaicin, zingerone [each TRP vanilloid-1 (TRPV1) agonist] and (-)-menthol [TRP melastatin-8 (TRPM8) agonist], which are contained in capsicum, ginger and peppermint, respectively, have an inhibitory action on nerve conduction without TRP channel activation. Taking into consideration that Kampo medicine contains many plant-derived chemicals, it is possible that this inhibits nerve conduction. The present study examined how several kinds of Kampo medicine and also its related chemicals affect compound action potentials (CAPs) recorded from the frog sciatic nerve by using the air-gap method. Daikenchuto, rikkosan, kikyoto and rikkunshito reduced the peak amplitude of the CAP in a concentration-dependent manner; daikenchuto had an IC50 value of 1.1 mg/ml. When examined at a concentration of 2 mg/ml, the extents of the reductions by daikenchuto, rikkosan, kikyoto and rikkunshito were 70, 30, 25 and 15%, respectively. Daikenchuto being the most effective in inhibiting CAPs is composed of three kinds of extract powder, ginseng, Japanese pepper and processed ginger, in which are contained not only TRPV1 but also TRP ankyrin-1 (TRPA1) agonists. When the actions of daikenchuto-related chemicals on frog CAPs were examined, a TRPV1 agonist piperine (in black pepper) at 70 µM reduced CAP peak amplitude by 20%, and TRPA1 agonists, allyl isothiocyanate (in wasabi) and cinnamaldehyde (in cinnamon), reduced the amplitude with the IC50 values of 1.4 mM and 1.2 mM, respectively. These results indicate that Kampo medicine has an ability to inhibit nerve conduction. It is suggested that this action of Kampo medicine, particularly daikenchuto, may be partly due to nerve conduction inhibition by plant-derived TRP agonists contained in Kampo medicine.

著者

山本 悟 西 光晴 佐々木 宏典 石川 浩三 安田 聖子 澄川 泰弘 岸下 裕輔 井田 唯香 吉田 充広 掛田 崇寛 石川 敏三

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.26, no.4, pp.215-221, 2011-12-10 (Released:2013-03-16)

参考文献数

17

被引用文献数

1 1

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We have newly developed a low-powered magnetic stimulator (MS) that is characterized by two different frequency modes: 2 kHz (low frequency) and 83 MHz (ultra-short wave). It is suggested that MS reduces rat neuropathic pain associated with the prevention of neuronal degeneration. However, little is known about certain mechanisms of MS, at least, applicable value of the analgesic approaches in clinical situation. Thus, we aimed to determine the analgesic effects of MS in human with shoulder stiffness. We recruited volunteers with shoulder stiffness (MS was applied once for 10 min.) and with acute pain (MS was applied once a day (10 min period) for 9 days. The trial study on analgesic effects in human of new magnetic therapeutic instrument (Angel Touch®) were examined. We examined safety of MS based on electrocardiographic testing and body surface temperature. By using the heart rate on the electrocardiogram, we used FFT analyzer to analyze low frequency components (LH: 0.05 - 0.15Hz) and high frequency components (HF: 0.15 - 0.45 Hz). Muscle shoulder stiffness has been improved by the continued irradiation without a thermal action. Based on the present study, we suggest that MS has beneficial analgesic effects in human, and that MS will be a useful approach to treatment for neurodegenerative disorder because it may relieve pain via improvement of functional modulation of pain-emotional system.

著者

住谷 昌彦 大住 倫弘 猪俣 一則 大竹 祐子 井上 玲央 土田 陸平 横島 弥栄子 東 賢志 阿部 博昭

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.34, no.1, pp.19-23, 2019-03-30 (Released:2019-06-11)

参考文献数

15

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The brain monitors motor outputs and sensory inputs about limb movements and information communication of limb movements between the motor system and the sensory system all along the line. This information communication of limb move­ments is called as the sensorimotor loop. In the normal condition, the sensorimotor loop maintains congruent. Recent advancement of cognitive neuroscience can propose that pathologic pain like as phantom limb pain can emerge and sustains and finally impairs patients’ quality of life when the loop becomes incongruent. We have treated phantom limb pain with the mirror visual feedback (MVF) and recently virtual reality (VR) treatment. The MVF and VR treatments can re–construct movement representations of a phantom limb and then improve phantom limb pain. We have successfully evaluated such movement representations of a phantom limb by assessing the intact upper limb movements on the basis of the bimanual coupling effect, which is physiologically equipped with the brain. The analgesic effect of the VR system is closely linked to the objectively–assessed reemergence of movement representations of a phantom limb.

著者

佐藤 純一

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.34, no.4, pp.312-315, 2019-12-20 (Released:2020-03-14)

参考文献数

16

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Chronic pain is known to get worse under the influence of weather change (tempera­ture, humidity, pressure). This is generally called “weather–related pain”. The author believes that the pressure sensor in the inner ear and the autonomic nervous system imbalance are involved in the mechanism of worsening pain and associated symptoms due to a decrease in atmospheric pressure. In addition, the activation mechanism of the cold receptor on skin occurs in chronic pain, which is considered to be the main role of the mechanism of aggravation of chronic pain under low tem­perature environments.

著者

後迫 宏紀 吉田 剛 長谷川 智彦 大和 雄 夏目 貴弘 小川 真弥 阿波賀 祐治 Hama Aldric 髙松 宏幸 松山 幸弘

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.35, no.1, pp.45-51, 2020-03-31 (Released:2020-05-06)

参考文献数

15

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Functional magnetic resonance imaging (fMRI) is expected as a biomarker of pain because it can objectively evaluate changes in cerebral blood flow associated with neuron activity against pain. We have developed pain models for cynomolgus macaques because it is more compatible with humans in regard to the structures and functions of brain regions which is suggested to be involved in pain in humans. Aside from humans, the cynomolgus macaques are the most widespread primate genus, ranging from Japan to North Africa. Since the macaques are the animal species closest to humans among those which can be used for invasive experiments, they are widely used to understand the mechanisms of the human brain. The purpose of this study is to elucidate pain–related brain activation regions in the macaque models using fMRI. Generally, pain testing in animal models has been based on avoidance behavior against pain stimuli. However, we identified pain–related brain activation regions using fMRI under propofol anesthesia as a more objective evaluation method. In the macaque model of chymopapain–induced discogenic low back pain, the activity of the insular cortex occurred in response to lumbar compression stimulation. In the macaque model of oxaliplatin–induced neuropathic cold hypersensitivity, activation of the insular cortex also occurred in response to cold stimuli. As a result of evaluating pregabalin, duloxetine and tramadol, only duloxetine showed behavioral effectiveness and suppressed activation of the insular cortex due to oxaliplatin–induced neuropathic pain. In the macaque model of postoperative pain, activation of the insula cortex was mainly activated by pressure stimulation. As a result of evaluating morphine, pregabalin and diclofenac, only morphine showed behavioral effectiveness and suppressed activa­tion of the insular cortex due to postoperative pain. However, macaques with naturally occurring endometriosis exhibited a pain response against pressure stimuli to the abdomen, and had activation of the thalamus. As a result of evaluating morphine, meloxicam and acetaminophen, only morphine showed behavioral effectiveness and suppressed activation of thalamus due to abdominal pain from endometriosis. It was suggested that the brain activation regions could change due to various conditions that can cause the pain, as the acute pain increased activation in the insula cortex and the chronic pain increased activation in the thalamus. This study demonstrated the usefulness of fMRI as a pain biomarker, and fMRI analysis using the macaques might provide an advantage for the translation of the findings to human patients. Therefore, these study will contribute to the development of new analgesics for each pain as well as to the progress in the areas of brain research.

著者

加藤 佳子 山川 真由美 長岡 由姫 加藤 滉

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.18, no.2, pp.71-75, 2003-08-31 (Released:2014-04-02)

参考文献数

4

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We reported four patients who received the treatment for severe pain with normal saline and/or distilled water injections. They suffered from various kinds of severe pain. The diagnoses were, a chest pain from bone metastases of terminal liver cancer (Case 1), a low back and leg pain from lumbar spinal canal stenosis (Case 2), a scar pain after thoracic drainage (Case 3) and a postherpetic pain in cervical region (Case 4). All patients received the treatment consisted of nonsteroidal anti-inflammatory drugs (NSAIDs) and pentazocine and/or continuous epidural block, but pain relief was a little and incomplete. While they requested more potent pain relieving measures, but received injections of normal saline and/or distilled water. They recognized that “analgesic” injections had either some effect or no effect, but their physicians thought of the complaints as “psychogenic”one. After consulting to our clinic, we informed them in detail about the treatments with morphine and/or codeine. All 4 patients received our proposal, oral codeine (Case 2, 3) or continuous intravenous/oral morphine (Case 1, 4) started. Pain effectively relieved in all cases with satisfaction. In the treatment of pain, the word, “believe the patient's report of pain”, is the most fundamental principle. When patients complain of pain, they really suffer from pain and want more potent or much doses of analgesic,not normal saline or distilled water ! At that time, physician should “believe the patient's report of pain” and provide reliable pain-relieving therapies.

著者

石氏 陽三

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.33, no.4, pp.315-322, 2018-12-28 (Released:2019-03-29)

参考文献数

34

被引用文献数

1

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Itch is defined as an unpleasant sensation that evokes the desire to scratch. Intractable itch and scratching can affect sleep, mood, and personal relationships, signifi­cantly reducing quality of life of the chronic pruritic diseases such as atopic derma­titis. Pruritogens activate certain receptors on small itch–selective unmyelinated C fibers. Peripheral itch stimuli are transmitted by sensory neurons to the spinal cord dorsal horn. After undergoing processing in the spinal cord, itch signals are conveyed through the spinothalamic tract to the thalamus and through the spinoparabrachial pathway to the parabrachial nucleus. Itch processing activates many brain areas such as the prefrontal cortex (PFC), supplementary motor area (SMA), premotor cortex (PM), primary motor cortex (MI), primary somatosensory cortex (SI), parietal cortex, cingulate cortex, precuneus, opercular cortex (OPC) including the secondary somato­sensory cortex (SII) and insular cortex (IC), claustrum, basal ganglia including the striatum, thalamus, and cerebellum. Itch was suppressed during and after scratching. It proposed two possible mechanisms by inhibitory circuits of the spinal dorsal horn and descending inhibitory pathway originated from brain such as periaqueductal gray matter (PAG), the raphe nuclei and locus ceruleus. Scratching temporarily relieves itch and can also be rewarding and even addictive. The degree of pleasure obtained by scratching is correlated with itch intensity. In addition, activation of areas of the brain reward system (eg, midbrain and striatum) is observed when an itch is scratched. In the brain, chronic itch modulates activation of particular brain areas, including the anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), and PFC; alternates functional brain connectivity; and can decrease the gray matter in itch–relating cortical areas, including the PFC and precuneus. These can play a role in processing the chronification of itch. In patients with atopic dermatitis, histamine–induced itch robustly activates the ACC and PFC. The degree of activation of these areas is closely correlated with disease activity. In addition, the degrees of activation of the PCC and precuneus are greater than those of healthy subjects. These changes might lead to neural sensitization to itch in the brain. One of the mechanisms of severe itch is skin hypersensitivity. Scratch usually inhibit itch in healthy subjects, however, it aggravates itch in the chronic pruritic diseases. This phenome­non is called ‘itch–scratch cycle’. Recent improved brain imaging studies demonstrate the brain mechanisms of chronic itch condition. A higher activity during scratching in chronic itch patients, versus healthy controls, was noted in brain regions related to motor control and motivation to act. The objectives of this review will be to address the new insight of brain mechanisms of chronic itch and the future prospect for the development of new drugs.

著者

牛田 享宏 野口 光一 細川 豊史 田口 敏彦 高橋 和久 住谷 昌彦 菊地 臣一

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.33, no.3, pp.183-192, 2018-09-15 (Released:2018-11-06)

参考文献数

11

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Chronic pain is one of the common health problems among the general population. Various mechanisms are involved in the pathophysiology of pain, and a correct understanding of its pathophysiology or cause is important for an optimal management of pain. In terms of the physiological anatomy, pain with physical ⁄ organic causes can be classified mainly as “nociceptive pain” or “neuropathic pain.” However, there is also pain that does not fall into either of these two categories. This type of pain is often considered as a third classification, but its definition has not been standardized globally. In Japan, this type of pain is often called “psychogenic pain,” even when the pain is not attributed to psychological factors. However, it may not be an appropriate term for this particular type of pain. Firstly, because there is no standardized definition, physicians differ in how they classify pain as “psychogenic.” Additionally, the term “psychogenic” could give negative impressions to patients, which can deteriorate the patient–physician relationship and may result in poor treatment outcomes. In this paper, we have discussed these problems and proposed a new term “cognitively perceived pain” for this third category of pain, with the aim to foster a more appropriate, and easy–to–understand classification of pain. “Cognitively perceived pain” encompasses all pain that is neither nociceptive nor neuropathic pain, including that described as centralized pain or sensory hypersensitivity, in addition to psychogenic pain according to its original meaning (i.e. pain attributable to psychological factors). Because pain is perceived in the brain, the presence of any pain implies the impairment or abnormality of cognition. The proposed term is straightforward to convey the essence of pain without including any negative–sounding words. We hope that this term and its concept will be widely accepted, and help to increase understanding of this poorly defined category of pain.

著者

城 由起子 松原 貴子

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.32, no.4, pp.246-251, 2017-12-20 (Released:2018-05-31)

参考文献数

20

被引用文献数

1 1

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Exercise therapy is recommended in the management of patients with chronic pain. However, there is little evidence supporting a relationship between changes in pain or physical disability and changes in physical performance by exercise therapy. Thus, exercise is thought to be involved it directly in the improvement of pain. Exercise has been shown to reduce the peripheral pain sensitivity in healthy subject. This effect, known as exercise–induced hypoalgesia (EIH), may be induced by the activation of central pain modulation systems. However, the effects of acute exercise in chronic pain conditions are heterogeneous and adverse. In patients with chronic pain, for example, exercise seems to decrease pain threshold. Notably, acute exercise followed by physical fatigue induces hyperalgesia. Therefore, regular exercise, rather than acute exercise, is recommended, in the management of patient with chronic pain.Physical inactivity is a perpetuating factor which can cause pain to become chronic. We investigated the relationship between intensity of physical activity in daily life and the function of central pain inhibitory systems. Our results suggested that the function of central pain inhibitory systems may decrease with a low amount of physical activity in women; therefore, maintaining physical activity may be more important for women than for men in preventing chronic pain.The effects and mechanisms of pain inhibition through regular exercise have been suggested using the animal model of pain. According to one of these suggested mechanisms, regular exercise increases the release of met–enkephalin in the rostral ventromedial medulla (RVM) and uses opioid receptors centrally to mediate analgesia. We investigated the influences on central pain inhibitory systems by regular exercise in subjects with chronic pain. While regular exercise for 2 weeks carried out three times a week improved the central pain modulation systems, it was ineffective if only done twice a week. However, an effect was seen if twice–weekly exercise continued for 3 weeks. Therefore, we conclude that increasing physical activity in daily life by regular exercise may be important in prevention and management of chronic pain.

著者

平田 幸一 團野 大介 菊井 祥二 鈴木 圭輔 竹島 多賀夫

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.35, no.2, pp.73-79, 2020-06-30 (Released:2020-08-03)

参考文献数

11

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Refractory chronic headaches greatly impair the quality of life of migraine patients and also reduce social productivity. To elucidate the pathophysiology of the supersensitive brain state of refractory migraine attacks, and to discover the treatment and prophylaxis for the refractory chronic migraine, we analyzed a brain electric field under the light stimulation–induced brain supersensitivity. As a result, we found suppression of the cortical hyperexcitation only in patients with migraine without aura. This result suggested that the suppression of the cortical hyperexcitation by cortical spreading depression may have a role for inhibition of excitation in limbic system, vestibular system and the vomiting center. Next, cranial autonomic symptoms in patients with migraine have recently received attention. We showed that central sensitization, assessed by central sensitization inventory questionnaire, was more prevalent in migraine patients with cranial autonomic symptoms compared with those without cranial autonomic symptoms, suggesting a possible role of central sensitization in comorbid autonomic symptoms in migraine. Central sensitization is postulated to participate in not only severe pain but also in various symptoms such as fatigue, sleep disturbances, anxiety and depres­sion in chronic pain syndrome. We believe our study results from migraine patients shed some light on the role of central sensitization in pathophysiology of chronic pain syndrome, but the elucidation of these relationships require further studies.

著者

橘高 裕貴 山野井 遊 富永 真琴

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.33, no.1, pp.47-57, 2018-03-30 (Released:2018-05-31)

参考文献数

24

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Crotamiton (N–ethyl–o–crotonotoluidide) has long been used as an anti–itch agent. However, the mechanism by which crotamiton exerts anti–itch effects is unknown. Based on recent studies showing that transient receptor potential (TRP) channels are involved in itch sensations, we hypothesized that crotamiton could affect the activity of TRP channels. In this study, we found that crotamiton strongly inhibits TRPV (vanilloid) 4 channel activity. Crotamiton also inhibited itch–related behaviors induced by the TRPV4–selective agonist GSK1016790A. In patch–clamp experiments we observed large TRPV4 currents following crotamiton washout. In this washout current, single–channel open probabilities and unitary current amplitudes of TRPV4 were increased, which together were suggestive of TRPV4 pore dilation. To explore whether TRPV4 pore dilation occurred, we performed cation replacement experiments in which whole–cell currents and reversal potentials were measured. Our observa­tion of increased cation influx and changes in reversal potentials upon crotami­ton washout indicated the presence of TRPV4 pore dilation. These results identified TRPV4 as a molecular target of crotamiton and demonstrated pore dilation of TRPV4 upon crotamiton washout.

著者

相澤 風花 中本 賀寿夫 徳山 尚吾

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.33, no.3, pp.203-213, 2018-09-15 (Released:2018-11-06)

参考文献数

47

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It has been accepted the fact that patients with chronic pain comorbid with depression or anxiety appeal profoundly severe pain condition more than healthful emotional condition. The critical treatment of chronic pain has not been appeared although noradrenergic and serotonergic neurons were discovered as a target of treatment such as depression or anxiety. Recently, the importance of function of the n–3 free fatty acids (FFAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid is focused on the novel target of chronic pain. However, the mechanism has not been elucidated. The G–protein coupled receptor 40 ⁄ free fatty acid receptor 1 (GPR40 ⁄ FFAR1), a receptor of middle–long chain FFAs including DHA, distribute in the brain of human and rodents. We previously reported that the GPR40 ⁄ FFAR1 suppressed not only various pain stimuli via activation of endogenous pain regulation systems but also depression–like behavior. Our previous study demonstrated that the GPR40 ⁄ FFAR1 knock–out mice show the persistent of mecha­nical allodynia after hind–paw incision. Furthermore, the GPR40 ⁄ FFAR1 knock–out mice show the abnormal emotional behaviors. Our results suggested that the GPR40 ⁄ FFAR1 has the potential of the novel therapeutic target of stress–induced chronic pain.

著者

川田 倫子 牛田 享宏 池内 昌彦 川上 照彦 山中 紀夫 池本 竜則 谷 俊一 小松 誠

出版者

日本疼痛学会

雑誌

PAIN RESEARCH (ISSN:09158588)

巻号頁・発行日

vol.21, no.3, pp.127-132, 2006-08-20 (Released:2013-10-24)

参考文献数

10

被引用文献数

3 6

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Hip joint associated pain is known to distribute widely in affected thigh or lower leg and generally not restricted in hip joint area.However detail feature of hip joint associated referred pain is not sufficiently clarified. Therefore the aim of this study is to characterize the types of distribution of hip joint related pain and to give our opinion about underlying neurophysiological mechanisms of hip joint referred pain. Of 36 severe osteo-arthritis joints, 83% of the joints showed remote pain area and 18% of the joints showed pain restricted only in inguinal area. Fourteen percent of the joints had far remote pain in lower leg area. L5 root block study was conducted in 7 cases. In all cases remote referred pains were attenuated at least 2 or 3 days and long lasting pain improvement was achieved in one case. These results suggest that referred pain observed in severe hip osteoarthritis cases may initially triggered by hip joint itself but prolonged referred muscle pain may become a possible generator for triggering and maintaining of mal-pain circuit.