[show abstract][hide abstract] ABSTRACT: Myofascial pain syndrome (MPS) is an important clinical condition characterized by chronic muscle pain and a myofascial trigger point (MTrP) located in a taut band (TB). However, its pathogenic mechanism is still unclear. We developed an animal model relevant to conditions of MPS, and analyzed the mechanism of the muscle pain in this model. We applied eccentric contraction (EC) to a rat's gastrocnemius muscle (GM) for 2 weeks, and examined the mechanical withdrawal thresholds, histological changes, and expressions and contents of nerve growth factor (NGF). The mechanical withdrawal threshold decreased significantly at the next day of first EC and continued up to 9 days after EC. TBs were palpable at 3 to 8 days after initiation of EC. In EC animals, necrotic and regenerating muscle cells were found significantly more than in control animals. In EC animals, NGF expressions in regenerating muscle cells and NGF contents of GM were significantly higher than control animals. Administration of NGF receptor (TrkA) inhibitor K252a showed significant suppression of mechanical hyperalgesia in EC animals. Repeated EC induced persistent mechanical muscle hyperalgesia associated with TB. NGF expressed in regenerating muscle cells may have an important role in persistent mechanical muscle hyperalgesia which might be relevant to pathogenesis of MPS. PERSPECTIVE: The present study shows that NGF expressed in regenerating muscle cells is involved in persistent muscular mechanical hyperalgesia. NGF-TrkA signaling in primary muscle afferent neurons may be one of the most important and promising targets for MPS.
The journal of pain: official journal of the American Pain Society 06/2011; 12(10):1059-68. · 3.78 Impact Factor
[show abstract][hide abstract] ABSTRACT: Objectives: To introduce the experimental model of trigger point [TrP] induced by repeated eccentric contractions [REC] in humans, rabbits, and rats, and to suggest a generalized hypothesis of the TrP formation in various tissues. Methods: In human subjects, REC of the extensor digitrum muscle of forearm were done with a load set on the middle fingers. In animal experiments [rabbit and rat], passive stretching during REC induced by electrical stimulation of the nerve was done using gastrocnemius muscle. Amplitude of reflex EMG of biceps femoris muscle was used for nociceptive response. Local ischemia was made by ligation of blood vessels. Results: After REC, a sensitive spot and palpable band appeared, and pressure-pain threshold was restrictedly reduced at the center of palpable band. Measurements of deep pain by focal current stimulation, pain sensation in human, and reflex electromyogram of biceps femoris were elicited by only at the depth of fascia. Electrical activities also recorded from the sensitive spot at the depth of fascia, and they were suppressed by acupuncture. Ischemic condition elongated the existence of sensitive spot and palpable band, and windup phenomena also observed. Conclusions: The tissue injuries and subsequent inflammation processes produced by the REC play an important role in the development of TrP, and ischemic condition could induce synaptic changes in the spinal cord. Sensitization of peripheral sensory receptors presumably polymodal receptors of the fascia and plastic changes and central sensitization might be a possible underlying mechanism of the TrP formation and referred pain phenomena.
[show abstract][hide abstract] ABSTRACT: We summarize the results from a series of investigations of Japanese style acupuncture and moxibustion therapies on symptoms of the common cold that have been conducted (FTLE 1999-03, supported by the Foundation for Training and Licensure Examination in Anma- Massage- Acupressure, Acupuncture and Moxibustion). We also discuss the various interventions and concerns that we faced during these investigations. The subjects were students and teachers. The pilot study (FTLE1999) of a two arm (real and non-treatment control) RCT at a Japanese acupuncture school showed that manual acupuncture to a specific needling point at the throat clearly reduced symptoms of the common cold. The first multi-center (five centers) RCT (FTLE 2000) revealed a significant reduction in cold symptoms, by general linear model analysis (between groups, P = 0.024). To reduce the technical variation, we employed indirect moxibustion to the neck points as a uniform intervention in the next project (FTLE 2001) without statistically significant results. Then we elongated the periods of treatment from 2 to a maximum of 12 weeks (FTLE 2002) with different interventions accompanied by 4 weeks follow-up. The results were still not statistically significant. As the final project, we tried to develop a new experimental design for individualized intervention by conducting n-of-1 trials using elderly subjects in a health care center but without detecting a clear effect. In conclusion, the safety of Japanese acupuncture or moxibustion was sufficiently demonstrated; however, a series of clinical trials could not offer convincing evidence to recommend the use of Japanese style acupuncture or moxibustion for preventing the common cold. Further studies are required as the present trials had several limitations.
Evidence-based Complementary and Alternative Medicine 01/2009; 5(4):481-9. · 1.72 Impact Factor
[show abstract][hide abstract] ABSTRACT: Acupuncture originated in China and is widespread throughout Asia. It is expected that a higher utilization of this remedy exists in these countries compared to Western countries. We conducted annual nationwide surveys from 2003 through 2006 on the utilization of acupuncture in Japan. Face-to-face interviews were conducted with 2000 individuals randomly chosen from the resident database. Annual utilization percentages, based on the number of respondents, from 2003 to 2006 were 6.5%, 4.8%, 6.4%, and 6.7%, respectively, while lifetime experiences determined in each surveys were estimated as 26.7, 19.4, 24.4 and 25.4, respectively. Respondents who had utilized acupuncture and/or moxibustion tended to be older than those who had no experience. Acupuncture was mainly used for musculoskeletal symptoms, and a detailed breakdown of the musculoskeletal symptoms identified in the 2005 survey showed 50.9% for low back pain, 35.9% for shoulder stiffness and 12.0% for knee pain. Reasons given for continuing therapy included the effective amelioration of symptoms, comfort of the procedure and low number of side-effects, while those who decided against continuing cited no improvement of symptoms, cost and lack of time for treatment. In conclusion, annual utilization of acupuncture and/or moxibustion was estimated at more than 6%, and the percentage of those with a lifetime experience was ∼25%, thus demonstrating the relatively higher utilization of the remedy in Japan over utilization in western countries. Application of the treatment for musculoskeletal problems and utilization by the older population were specific standouts of the use of acupuncture and/or moxibustion in Japan.
Evidence-based Complementary and Alternative Medicine 08/2008; 7(4):493-500. · 1.72 Impact Factor
[show abstract][hide abstract] ABSTRACT: Acupuncture has recently been attracting more and more people throughout the world as an alternative treatment, however little is known about its physiological activities (i.e. immune system). We examined acupuncture both quantitatively and qualitatively by measuring CD-positive cell counts and cytokine expression levels in the blood, to determine the activity of T cells, B cells, macrophages and natural killer (NK) cells. Fifteen milliliters of peripheral blood obtained from 17 healthy volunteers aged 21-51 years, were analyzed using flow cytometry before and after acupuncture treatment. There was a statistically significant increase in the number of CD2(+), CD4(+), CD8(+), CD11b(+), CD16(+), CD19(+), CD56(+) cells as well as IL-4, IL-1beta and IFN-gamma levels in the cells after acupuncture stimulation of meridian points. These observations indicate that acupuncture may regulate the immune system and promote the activities of humoral and cellular immunity as well as NK cell activity. In this article, we discussed how acupuncture regulated leukocyte numbers and functions since they are considered to be potential indicators for evaluating complementary and alternative medicine.
Evidence-based Complementary and Alternative Medicine 01/2008; 4(4):447-53. · 1.72 Impact Factor
[show abstract][hide abstract] ABSTRACT: The analgesic effects of moxibustion on an experimental model of osteoarthritis of the knee were investigated.
Male Wistar rats (n=36, 296-421 g) were used. Intra-articular injection of mono-iodoacetic acid (MIA) was performed to induce knee osteoarthritis. Indirect moxibustion was applied to the lateral aspect of the knee joint every other day for 28 days (14 treatments). Weight bearing of the hind legs was measured directly by the downward pressure applied to footplates, using an Incapacitance Tester. Morphine was injected for testing the validity of weight bearing as a pain measure, and naloxone was used to examine the participation of endogenous opioids in the mechanism of moxibustion analgesia. Data were analysed by calculating the area under the curve.
Injection of MIA significantly reduced weight bearing. No analgesic effects of moxibustion were observed during the initial 7 days (unpaired t test, P=0.83). Continued moxibustion treatments increased weight bearing at the 14th day significantly, and this effect continued until the end of the experiment on the 28th day (P<0.05). A single moxibustion treatment had no immediate effect on weight bearing. The analgesia due to the cumulative effect of moxibustion was antagonised by naloxone injection. Morphine injection in control MIA injected rats increased weight bearing to the normal range, confirming the validity of the measurements.
These results highlight the importance of repeated moxibustion treatments for pain relief in experimental knee osteoarthritis and suggest the existence of sustained inhibitory modulation by endogenous opioids in the moxibustion group.
Acupuncture in Medicine 12/2007; 25(4):175-83. · 1.05 Impact Factor
[show abstract][hide abstract] ABSTRACT: The mechanism of acupuncture analgesia (AA) is one of the most widely researched topics in complementary and alternative medicine (CAM) based on modern medical methodology. Endogenous opioid-mediated mechanisms of acupuncture have been well established since the 1970s. In this review, we have covered the progress of AA research by Japanese investigators. In particular, we have reviewed the physiological basis of analgesic effects induced by acupuncture and moxibustion, including the actions of endogenous opioid and diffuse noxious inhibitory controls (DNICs), and the afferent fibers participating in acupuncture and moxibustion stimuli are discussed.
Evidence-based Complementary and Alternative Medicine 09/2007; 6(1):11-7. · 1.72 Impact Factor
[show abstract][hide abstract] ABSTRACT: We examined how acupuncture affected the blood flow of muscle, kidney, stomach, small intestine, brain, lung, heart, spleen and liver. Wistar rats anesthetized with urethane (n = 27) were allocated into the control (n = 10), ST-7 (Hsia-Kuan, n = 10) and LI-4 (Hoku, n = 7) groups. To measure organ blood flow, colored microspheres (CMS) were injected through a catheter positioned in the left ventricle and blood samples were drawn from the femoral artery. Yellow CMS (3.6-4.2 x 10(5)) and blue CMS (6.0-6.9 x 10(5)) were injected at intervals of about 30 min. An acupuncture needle (varphi 340 mum) was inserted into the left ST-7 point (left masseter muscle) or the right LI-4 point after the first sampling and left for about 30 min (10 twists at 1 Hz, 2-min intervals). The mean blood flow of nine organs varied widely from 4.03 to 0.20 (ml/min/g). Acupuncture to the ST-7 produced significant changes of the blood flow (percentage change from baseline) in the muscle, kidney, brain and heart (P < 0.05, versus control), but those of LI-4 were not significant. The blood flow of the left masseter muscle after acupuncture to ST-7 (left masseter muscle) tended to increase (P = 0.08). Changes in blood pressure during the experimental periods were almost similar among these three groups. Acupuncture stimulation increases the blood flow of several organs by modulating the central circulatory systems, and the effects differed with sites of stimulation.
Evidence-based Complementary and Alternative Medicine 06/2007; 6(1):77-83. · 1.72 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to examine the immediate effect of single acupuncture stimulation to the most painful point in patients with low back pain.
A randomised, evaluator-blinded, sham controlled clinical trial was conducted in which 31 patients with low back pain were randomly allocated to either an acupuncture group (n = 15) or a sham acupuncture group (n = 16). Both acupuncture and sham acupuncture were performed at the most painful point on the lower back of the subjects. For the acupuncture group, a stainless steel needle was inserted to a depth of 20 mm and manually stimulated (sparrow pecking method) for 20 seconds, while for the sham treatment a guide tube without a needle was placed at the point and tapped on the skin. Changes in low back pain were evaluated with a visual analogue scale (VAS) and the Schober test. Participants were also asked if they felt the needling sensation or not. The therapy and the evaluation were independently performed by two different acupuncturists.
VAS score and the Schober test score showed significant improvement after treatment as compared with the sham group (P = 0.02, 0.001, respectively). There were no significant differences in the needling sensation between the acupuncture and sham group.
These results suggest that acupuncture at the most painful point gives immediate relief of low back pain.
Acupuncture in Medicine 10/2006; 24(3):103-8. · 1.05 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to investigate the in vivo relation between muscle hardness during an electrically induced contracting state and neuromuscular functions (M-wave and developed tension). Sixteen Sprague-Dawley rats were deeply anesthetized with urethane. Muscle hardness was measured quantitatively at the mid-portion of the gastrocnemius (GS) muscle during tetanic contractions induced by electrical stimulation (50 Hz, 100 micros duration) of the sciatic nerve or of the muscle directly. The M-wave was recorded with a pair of wire electrodes inserted into the muscle, and the developed tension was monitored with a push-pull gauge. Muscle hardness, M-wave amplitude and developed tension increased rapidly with the onset of nerve stimulation. Similar but intensity-dependent increases in muscle hardness and tension were observed following direct tetanic stimulation of the muscle. The hardness measured during nerve stimulation was correlated with the amplitude of the M-wave (r = 0.62, P < 0.0001) and the developed tension (r = 0.85, P < 0.0001). These phenomena were suppressed by pancuronium treatment (2 mg/ml, i.v.). These results suggest that muscle tension might be the most important factor for transcutaneously measured muscle hardness induced by tetanic muscle contraction.
[show abstract][hide abstract] ABSTRACT: The mechanisms of action of acupuncture and moxibustion as reported by Japanese researchers are reviewed. The endogenous opioid-mediated mechanisms of electroacupuncture (EA) as used in China are well understood, but these are only one component of all mechanisms of acupuncture. These studies emphasize the similarity of the analgesic action of EA to various sensory inputs to the pain inhibition mechanisms. In Japanese acupuncture therapy, careful detection of the acupuncture points and fine needling technique with comfortable subjective sensation are considered important. The role of polymodal receptors (PMR) has been stressed based on the facts that PMRs are responsive to both acupuncture and moxibustion stimuli, thermal sensitivity is essential in moxibustion therapy, and the characteristics of acupuncture points and trigger points are similar to those of sensitized PMRs. Acupuncture and moxibustion are also known to affect neurons in the brain reward systems and blood flow in skin, muscle, and nerve. Axon reflexes mediated by PMRs might be a possible mechanism for the immediate action of acupuncture and moxibustion. Reports on the curative effects of acupuncture on various digestive and urological disorders are also reviewed briefly.
Journal of Pharmacological Sciences 02/2006; 100(5):443-59. · 2.15 Impact Factor
[show abstract][hide abstract] ABSTRACT: Transcutaneous pressure with pressure probes of arbitrary diameters have been commonly used for measuring the threshold and magnitude of muscle pain, yet this procedure lacks scientific validation. To examine the valid probe dimensions, we conducted physiological experiments using 34 human subjects. Pin-prick pain, pressure pain threshold (PPT) to pressure probes of various diameters, heat pain threshold, and electrical pain threshold of deep tissues were measured before and after application of surface lidocaine anesthesia to the skin surface over the brachioradial muscle in a double-blinded manner. The anesthesia neither affected PPT with larger probes (diameters: 1.6 and 15 mm) nor increased electric pain threshold of deep structures, whereas it diminished pain count in pin-prick test and PPT with a 1.0 mm diameter probe, suggesting that mechanical pain thresholds measured with 1.6 and 15 mm probes reflect the pain threshold of deep tissues, possibly muscle. Pain thresholds to heat did not change after application of the anesthesia. These results suggest that larger pressure probes can give a better estimation of muscular pain threshold.
Somatosensory and Motor Research 01/2006; 22(4):299-305. · 0.93 Impact Factor
[show abstract][hide abstract] ABSTRACT: Therapeutic benefits of acupuncture for chronic pain patients have been clearly identified in recent clinical trials. Underlying mechanisms of acupuncture action mediated by endogenous opioids have been well demonstrated. The existence of pain inhibitory systems in the central nervous system has also been clarified and acupuncture seems to be a potent stimulus for activating the analgesic systems, although the pain mechanisms in acute and chronic states are essentially different. On the other hand, the exact nature of the acupuncture point still remains unclear. Here, we propose a key role of polymodal receptors (PMR) in acupuncture and moxibustion and offer a rational explanation of the acupuncture point as a sensitised PMR.Moxibustion (burning of moxa) therapy has been shown by medical historians to predate the use of acupuncture, and the meridian theory developed in association with moxibustion treatment. A variety of sensory receptors are activated by acupuncture and/or moxibustion, but there are very few that can be excited by both stimuli. PMRs are one of the most promising candidates. The functional characteristics of PMRs correspond with those of acupuncture action in the periphery; and tender or trigger points, one of the primitive features of acupuncture points, are assumed to be the sites of sensitised PMRs. Diffuse noxious inhibitory control (DNIC) is proposed as a possible mechanism of immediate action of acupuncture, and inputs for the development of DNIC seem to be the PMRs.In our experimental model, repeated eccentric contractions of muscle produced local tenderness at the palpable band and induced a typical referred pain pattern on application of pressure. Repeated indomethacin injections inhibited the production of the experimental trigger point.These lines of evidence suggest that the acupuncture points are the sites where the PMRs are sensitised and that such conditions might be repeatedly produced by various biomechanical stressors, insufficient blood supply and metabolic products.
[show abstract][hide abstract] ABSTRACT: To determine the preventive and curative effects of manual acupuncture on the symptoms of the common cold.
Students and staff in five Japanese acupuncture schools (n=326) were randomly allocated to acupuncture and no-treatment control groups. A specific needling point (Y point) on the neck was used bilaterally. Fine acupuncture needles were gently manipulated for 15 s, evoking de qi sensation. Acupuncture treatments were performed four times during the 2-week experimental period with a 2-week follow-up period. A common cold diary was scored daily for 4 weeks, and a common cold questionnaire was scored before each acupuncture treatment and twice at weekly intervals. A reliability test for the questionnaire was performed on the last day of recording.
Five of the 326 subjects who were recruited dropped out. The diary score in the acupuncture group tended to decrease after treatment, but the difference between groups was not significant (Kaplan-Meier survival analysis, log rank test P=0.53, Cox regression analysis, P>0.05). Statistically significantly fewer symptoms were reported in the questionnaire by the acupuncture group than control group (P=0.024, general linear model, repeated measure). Significant inter-centre (P<0.001, general linear model) and sex (P=0.027, general linear model) differences were also detected. Reliability tests indicated that the questionnaire with 15 items was sufficiently reliable. No severe adverse event was reported.
This is the first report of a multi-centre randomized controlled trial of acupuncture for symptoms of the common cold. A significantly positive effect of acupuncture was demonstrated in the summed questionnaire data, although a highly significant inter-centre difference was observed. Needling on the neck using the Japanese fine needle manipulating technique was shown to be effective and safe. The use of acupuncture for symptoms of the common cold symptoms should be considered, although further evidence from placebo controlled RCTs is required.
Complementary Therapies in Medicine 12/2004; 12(4):181-8. · 2.09 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to develop an experimental model of myofascial trigger points to investigate their pathophysiology.
Fifteen healthy volunteers who gave informed consent underwent repetitive eccentric exercise of the third finger of one hand (0.1 Hz repetitions, three sets at five minute intervals) until exhaustion. Physical examination, pressure pain threshold, and electrical pain threshold of the skin, fascia and muscle were measured immediately afterwards and for seven days. Needle electromyogram (EMG) was also recorded in a subgroup of participants.
Pressure pain thresholds decreased to a minimum on the second day after the exercise, then gradually returned to baseline values by the seventh day. On the second day, a ropy band was palpated in the exercised forearm muscle and the electrical pain threshold of the fascia at the palpable band was the lowest among the measured loci and tissues. Needle EMG activity accompanied with dull pain sensation was recorded only when the electrode was located on or near the fascia of the palpable band on the second day of exercise.
These results suggest that eccentric exercise may yield a useful model for the investigation of the myofascial trigger points and/or acupuncture points. The sensitised nociceptors at the fascia of the palpable band might be a possible candidate for the localised tender region.
Acupuncture in Medicine 04/2004; 22(1):2-12; discussion 12-3. · 1.05 Impact Factor
[show abstract][hide abstract] ABSTRACT: To compare the effects of real acupuncture to tender points for neck and shoulder pain and stiffness (Japanese: katakori) with those of sham acupuncture.
Thirty-four volunteers from an acupuncture school with complaints of chronic pain and stiffness, who had no arm symptoms and gave informed consent, were randomly allocated to acupuncture or sham groups. Acupuncture or sham acupuncture was applied to the tender points once a week for 3 weeks. In the acupuncture group the acupuncture needle was inserted to the muscle, then the sparrow pecking technique was applied five times. Sham acupuncture was done without insertion of the needle. Dull pain and stiffness were evaluated by visual analog scale (VAS) before, and every 2 days after the first needling for 1 month. Pressure pain threshold on the tender points was measured before and after each treatment.
There was no statistical difference of VAS scores between acupuncture and sham groups 9 days after the last treatment. However, the acupuncture group showed significant reduction of VAS scores immediately after and/or 1 day after the real acupuncture treatments (P<0.01). The effect tended to be prolonged after repeated treatment. Pressure pain thresholds tended to increase after real acupuncture treatment but not after sham acupuncture.
Acupuncture applied to tender points appears to have short-term effects on neck and shoulder pain and stiffness, but this study was unable to demonstrate any long-term superiority over sham acupuncture.
Complementary Therapies in Medicine 12/2002; 10(4):217-22. · 2.09 Impact Factor
[show abstract][hide abstract] ABSTRACT: The effect of indomethacin on the development of delayed onset muscle soreness (DOMS) and localized sensitive region produced by eccentric exercise was examined in lightly anesthetized rabbits (n=12, 2.0-3.3 kg). Repeated eccentric contractions of the gastrocnemius (GS) muscle were made by manual extensions during the tetanic contractions induced by electrical stimulation of the tibial nerve. The development of DOMS was confirmed by evoked reflex EMG in the biceps femoris (BF) muscle elicited by a quantitative manual extension of the GS muscle. The distribution of thresholds for the evoked BF EMG was measured by focal electrical stimulations of the GS muscle. Indomethacin (5 mg/kg in 2% sodium bicarbonate) or a vehicle was injected subcutaneously before, during, and after the exercise (a total of 60 mg/kg in 12 doses). A clear ropy taut band was palpated at the GS muscle on the second day after the exercise and a localized sensitive region for evoked BF EMG was detected at the depth of the fascia of the band in the exercise and vehicle groups, whereas no such phenomena appeared in the control and indomethacin groups. The palpable band and sensitive region disappeared on the seventh day after the exercise. That indomethacin inhibits the development of DOMS and the localized sensitive region suggests that a sensitization of polymodal-type nociceptors in the fascia mediated by prostaglandins is a possible mechanism for the development of DOMS and the localized sensitive region.
The Japanese Journal of Physiology 05/2002; 52(2):173-80. · 1.04 Impact Factor
[show abstract][hide abstract] ABSTRACT: The participation of polymodal-type receptor (PMR) in the action of acupuncture and moxibustion (A&M) was briefly reviewed and a working hypothesis was proposed. The PMR is known as a kind of nociceptor, and is responsive to mechanical (acupuncture), thermal (moxibustion) and chemical stimuli, and its sensory terminals are free nerve endings and exist in various tissues of the entire body. Selective activation of the PMR produced the de-qi sensation (a kind of deep pain) and neurogenic inflammation (flare and wheal), and considered as an input of the endogenous pain inhibition, autonomic, immune and endocrine functions. These characteristics of PMR are in agreement with a possible candidate of A&M. One of the functional characteristics of acupuncture points is its tenderness (ah-shi points) and its close relation to the trigger points. The sensitization of PMR is suggested to be the major cause of formation of trigger points, so if one chooses the acupuncture (trigger) points as the treatment loci, the sensitized PMR are activated more easily by gentle A&M procedures and activate various bio-regulatory systems more effectively. Thus, the present PMR hypothesis offers a rational explanation of functional meanings of the acupuncture (trigger) points.
[show abstract][hide abstract] ABSTRACT: Numerous studies have demonstrated that acupuncture and moxibustion induce analgesic effects. This study examined whether diffuse noxious inhibitory controls (DNIC) participated in acupuncture and moxibustion induced-analgesia. Single unit extracellular recordings from neurons in the trigeminal nucleus caudalis of urethane-anesthetized Wistar rats were obtained with a glass micropipette. A total of 52 single units, including 36 wide dynamic range (WDR), 5 nociceptive specific (NS) and 11 low-threshold mechanoreceptive (LTM) units were examined. During noxious test stimulation (cutaneous pinch or electrical stimulation), acupuncture, moxibustion or pinch stimulation was applied as the conditioning stimulus to the remote area of the receptive fields. When the conditioning stimulation induced rapid suppression of noxious receptive field stimulation response, examination revealed that various areas of the entire body were affected and suppression increased in an intensity-dependent manner. These features resemble DNIC phenomena. The suppression was observed on both WDR and NS neurons but not on LTM neurons. Eight of 16 WDR neurons examined were inhibited by acupuncture, five of 14 by moxibustion, and seventeen of 21 by pinching stimulation. Of the NS neurons, one of 2 units examined was suppressed by acupuncture, one of 2 by moxibustion, and two of 3 by pinch stimulation. Pinch stimulation induced the most profound suppression followed by manual acupuncture. Moxibustion induced moderate suppression with a long induction time. These results suggest that DNIC may be involved in the analgesic mechanism of acupuncture and moxibustion.
The Japanese Journal of Physiology 03/2000; 50(1):133-40. · 1.04 Impact Factor
[show abstract][hide abstract] ABSTRACT: Electrical stimulation of the nucleus submedius (Sm) has been shown to suppress the viscerosomatic reflex (VSR), which is evoked by colorectal distension (CRD). We have examined the effects of focal electrical stimulation (0.3 ms, 50 Hz, 100 microA, 10 s) of the Sm and the periaqueductal gray (PAG) on the excitatory responses evoked by CRD in spinal dorsal horn neurons within the L6-S1 region in the urethane-anesthetized Wistar rats. Extracellular recordings were made from 32 spinal excitatory CRD responses. All of these neurons were convergent neurons with cutaneous receptive fields. The majority of the neurons (27/32) were wide dynamic range (WDR) neurons (responding to noxious and non-noxious cutaneous stimuli) while the remaining five neurons were nociceptive specific (NS) neurons (responding only to noxious cutaneous stimuli). The effects of electrical stimulation applied to 28 sites within the Sm were assessed for spinal neurons. Electrical stimulation in seven sites within the Sm (25%) inhibited the CRD excitatory response of dorsal horn neurons, while in two sites (7%) the same stimulation yielded facilitation. Electrical stimulation in the majority of the sites in the Sm (19/28, 68%) did not affect spinal excitatory CRD responses. On the other hand, electrical stimulation of the PAG clearly inhibited 20 of 22 (90%) CRD excitatory responses. These results suggest that the majority of Sm neurons may suppress VSR activity at a supraspinal reflex center rather than via a descending inhibition of spinal visceral nociceptive transmission, as is the case for the PAG.
Brain Research 08/1999; 834(1-2):112-21. · 2.88 Impact Factor