Josie Resende Torres Silva

Analgesia Induced by 2- or 100-Hz Electroacupuncture in the Rat Tail-Flick Test Depends on the Activation of Different Descending Pain Inhibitory Mechanisms

UNLABELLEDnWe evaluated the effectiveness of intrathecal antagonists of α1- (WB4101) and α2- (idazoxan) adrenoceptors and serotonergic (methysergide), opioid (naloxone), muscarinic (atropine), GABA(A) (bicuculline) and GABA(B) (phaclofen) receptors in blocking 2- or 100-Hz electroacupuncture (EA)-induced analgesia (EAIA) in the rat tail-flick test. EA was applied bilaterally to the Zusanli and Sanyinjiao acupoints in lightly anesthetized rats. EA increased tail-flick latency, where the effect of 2-Hz EA lasted longer than that produced by 100-Hz EA. The 2-Hz EAIA was inhibited by naloxone or atropine, was less intense and shorter after WB4101 or idazoxan, and was shorter after methysergide, bicuculline, or phaclofen. The 100-Hz EAIA was less intense and shorter after naloxone and atropine, less intense and longer after phaclofen, shorter after methysergide or bicuculline, and remained unchanged after WB4101 or idazoxan. We postulate that the intensity of the effect of 2-Hz EA depends on noradrenergic descending mechanisms and involves spinal opioid and muscarinic mechanisms, whereas the duration of the effect depends on both noradrenergic and serotonergic descending mechanisms, and involves spinal GABAergic modulation. In contrast, the intensity of 100-Hz EAIA involves spinal muscarinic, opioid, and GABA(B) mechanisms, while the duration of the effects depends on spinal serotonergic, muscarinic, opioid, and GABA(A) mechanisms.nnnPERSPECTIVEnThe results of this study indicate that 2- and 100-Hz EA induce analgesia in the rat tail-flick test activating different descending mechanisms at the spinal cord level that control the intensity and duration of the effect. The adequate pharmacological manipulation of such mechanisms may improve EA effectiveness for pain management.

The integrity of the anterior pretectal nucleus and dorsolateral funiculus is necessary for electroacupuncture-induced analgesia in the rat tail-flick test

Previous studies have indicated that the anterior pretectal nucleus (APtN) is implicated in pathways that descend through the dorsolateral funiculus (DLF) to modulate nociceptive inputs in the spinal dorsal horn. The activation of descending inhibitory mechanisms also seems to be involved in electroacupuncture (EA)‐induced analgesia. This study utilized the tail‐flick test to examine the changes produced by DLF lesion or injection of 2% lidocaine into the APtN in the analgesia induced by 2 or 100 Hz EA applied to the Zusanli (ST36) and Sanyinjiao (SP6) acupoints in lightly anesthetized rats. Tail‐flick latency was significantly increased by EA, the effect of 2 Hz EA lasting longer than that produced by 100 Hz EA. The effect of either 2 or 100 Hz EA did not occur in DLF lesion rats. The effect of 2 Hz EA did not occur in rats with neural block of the whole or dorsal APtN. In contrast, the effect of 100 Hz EA was reduced in rats with neural block of the whole APtN, but remained unchanged in rats with neural block of the dorsal APtN. We thus conclude that the integrity of the APtN and DLF is necessary for EA‐induced analgesia in the rat tail‐flick test. In addition, the integrity of the dorsal APtN is necessary for the analgesic effect of 2 but not 100 Hz EA.

The antinociceptive effect of electroacupuncture at different depths of acupoints and under the needling surface

BackgroundThe stimulation of acupoints along the meridians, but not the non-acupoints outside of the meridians, produces analgesia. Although the acupoint is defined at the body surface, the exact location of the acupoints is not known. This study aims to examine whether the intensity and duration of the analgesic effect of electroacupuncture (EA) at the Zusanli (ST36) and Sanynjiao acupoints (SP6) change according to the depth of the stimulation.MethodsNinety-six male Wistar rats classified as responders were arbitrarily allocated into 16 groups of six rats each. Six groups received EA with uninsulated acupuncture needles (type I) or needles that were immersed in varnish and had the varnish circularly peeled 0.2 mm from the tip (type II), 0.2 mm at 3 mm (type III) or 5 mm (type IV) from the tip, or 0.2 mm at 5 and 1 mm from the tip (type V), or EA sham for 20 min. Five groups received injection of formalin into the acupoint bilaterally at 5 mm or 1 mm deep into ST36, 5 mm below ST36 but inserting the needle at 45° to the skin surface, or 5 mm deep into non-acupoints. The remaining groups received intraplantar injection of saline, 1% or 2.5% formalin. The analgesic effects were measured by the rat tail-flick test.ResultsThe bilateral stimulation of ST36 and SP6 by uninsulated or insulated needles produced analgesia in the rat tail-flick test. The stronger and longer lasting effects occurred after EA with the types I and V needles, or injection of formalin 5 mm deep into ST36. The remaining needles produced weaker and shorter lasting effects. Slow analgesic effect also occurred after formalin injection at 1 mm or 5 mm below ST36 by inserting the needle at 45° to the skin surface.ConclusionThe experimental results suggest that the efficacy of the EA stimulation depends on the spatial distribution of the current density under the needling surface rather than only the acupoint or the depth of needling.

The combined effect of acupuncture and Tanacetum parthenium on quality of life in women with headache: randomised study

Background The aim of the present study was to investigate the efficacy and tolerability of acupuncture (AC), Tanacetum (TAN) or combined treatment on quality of life in women with chronic migraine (CM). Methods A total of 69 women volunteers were randomly divided into 3 groups: AC, acupuncture administered in 20 sessions over 10u2005weeks (n=22); TAN, at 150u2005mg/day (n=23); and AC+TAN (n=23). The primary outcome was Short-Form 36 (SF-36) quality of life assessment score. Secondary outcomes included the Migraine Disability Assessment (MIDAS) and visual analogue scale (VAS) score experienced after randomisation. Results AC+TAN was statistically significantly more effective than AC or TAN alone in overall health-related quality of life (SF-36; p<0.05), on MIDAS score (−35.1 (10.6) AC vs −24.8 (11.7) TAN vs −42.5 (9.8) AC+TAN; p<0.05) and in reducing the mean score of pain on VAS (−5.6 (2.4) AC vs −3.7 (2.1) TAN vs −6.4 (3.1) AC+TAN; p<0.05). Conclusions The present work shows an improvement of the quality of life and better analgesic effect of acupuncture combined with TAN treatment on migraine pain in women when compared with acupuncture or TAN alone.

Analgesia induced by 2- or 100-Hz electroacupuncture in the rat tail-flick test depends on the anterior pretectal nucleus.

AIMSnThe anterior pretectal nucleus (APtN) and electroacupuncture (EA) activate descending mechanisms to modulate nociceptive inputs in the spinal dorsal horn. This study examines qualitatively whether mechanisms in the APtN participate in the EA-induced analgesia in rats.nnnMAIN METHODSnThe tail-flick test was utilized to examine the changes produced by non-selective antagonists of serotonergic (methysergide, 37 pg), muscarinic (atropine, 10 ng) and opioid (naloxone, 10 ng) receptors; selective antagonists against μ (CTOP, 6.4 μg), δ (ICI174,864, 6.9 μg) or κ (nor-BNI, 7.3 μg); 5HT1 (methiothepin, 0.47 μg), 5HT2 (ketanserin, 5.4 μg), or 5HT3 (MDL 72222, 15.7 μg); and GABAA (bicuculline, 150 ng) receptors injected into the dorsal (d) or ventral (v) APtN on the antinociception induced by a 20-min EA applied at 2- or 100-Hz frequency to the Zusanli and Sanyinjiao acupoints.nnnKEY FINDINGSnThe 2-Hz EA-induced analgesia was blocked by naloxone, CTOP or atropine, was less intense after bicuculline, was shorter after methysergide or methiothepin in dAPtN, and was less intense after methysergide, methiothepin and bicuculline in vAPtN. The 100-Hz EA-induced analgesia was less intense after methysergide, methiothepin and CTOP in vAPtN, and remained unchanged after injection of the antagonists into the dAPtN.nnnSIGNIFICANCEnThe 2-Hz EA-induced analgesia utilizes cholinergic muscarinic, μ-opioid, GABAA and 5-HT1 mechanisms in the dAPtN and μ-opioid and 5-HT1 mechanisms in the vAPtN, while 100-Hz EA-induced analgesia utilizes μ-opioid and 5-HT1 mechanisms in the vAPtN but does not utilize them in the dAPtN.

Retrosplenial Cortex is Involved in Analgesia Induced by 2- but not 100-Hz Electroacupuncture in the Rat Tail-Flick Test

This study examined whether or not the antinociceptive effect of 2- or 100-Hz electroacupuncture (EA) depends on the integrity of the retrosplenial cortex (RSC). Rats were taken for determination of tail-flick latency before and after injection of saline or 2% lidocaine (0.25 μl) into the retrosplenial cortex (RSC) bilaterally. Five minutes later, they were submitted to a 20-minute period of 2 Hz, 100 Hz, or sham EA at the Zusanli and Sanyinjiao acupoints bilaterally, and tail-flick latency was measured within 30 seconds after the end of stimulation and at 5-minute intervals for up to 30 minutes. EA at a frequency of either 2 or 100 Hz induced a strong and long-lasting inhibition of the tail-flick reflex in rats treated with saline (0.25 μl) injected into the RSC. The analgesia produced by 2-Hz EA lasted for a shorter time in lidocaine-treated rats. By contrast, RSC impairment did not change the analgesic effect of 100 Hz EA. The integrity of the RSC is implicated in the duration of analgesia induced by low-frequency EA but is not essential for the analgesic effects evoked by high-frequency EA.

Effect of Acupuncture at Tender Points for the Management of Fibromyalgia Syndrome: A Case Series

BACKGROUNDnAffecting more women than men, fibromyalgia syndrome (FMS) is a rheumatic disorder characterized by chronic, diffuse and widespread musculoskeletal pain, and its pathogenesis is still unknown. Among the recommended treatments, acupuncture (for its analgesic effects) is an effective option for reducing the pain sensitivity and improving quality of life. Therefore, this study aimed to investigate whether acupuncture at tender points could effectively manage FMS.nnnMETHODSnEight female patients, with a previous diagnosis of fibromyalgia, underwent an initial assessment involving pressure algometer measurements for pain tolerance and questionnaires [Fibromyalgia Impact Questionnaire (FIQ), Heath Assessment Questionnaire (HAQ), Beck Depression Inventory (BDI), and Beck Anxiety Inventory (BAI)], followed by treatment. Over a 2-month period, acupuncture was performed once per week at five tender points, located bilaterally at the occipital bone, trapezius, rhomboid, upper chest and lateral epicondyle. At the end of treatment, the participants underwent a reassessment for a final review of the applied methods.nnnRESULTSnWe observed a reduction in the pain threshold and sensitivity and improvement in the areas of anxiety and depression and quality of life, which were demonstrated using the FIQ, BDI and BAI but not the HAQ.nnnCONCLUSIONnThe results demonstrated the effectiveness of tender-point acupuncture treatment on the patients overall well-being, not only by improving quality of life, but also by reducing the pain sensitivity of FMS.

Antinociceptive effects of low-level laser therapy at 3 and 8 j/cm2 in a rat model of postoperative pain: possible role of endogenous Opioids

Low‐level laser therapy (LLLT) is the direct application of light to stimulate cell responses (photobiomodulation) to promote tissue healing, reduce inflammation, and induce analgesia; the molecular basis for these effects of LLLT remains unclear. The objective of this study was to evaluate the analgesic effect of LLLT in the rat plantar incision model of postoperative pain as well as to investigate some of the possible mechanisms involved in this effect. Wistar rats were submitted to plantar incision and treated with LLLT (830u2009nm, continuous‐mode, 30u2009mW/cm2, 1–12u2009J/cm2). Postoperative thermal and mechanical hypersensitivity were monitored for 24 hours post‐incision. In addition, the animals were pretreated with saline, naloxone (a nonselective opioid receptor antagonist; 20u2009µg/5u2009µl) or methysergide (5‐HT2C, 5‐HT2A, 5‐HT7, 5‐HT5a, 5‐HT6, and 5‐HT1F receptors antagonist; 30u2009µg/5u2009µl). Moreover, 24 hours after incision and treatment, the TNF‐α and IL‐1β levels in serum were evaluated. Our results demonstrate, for the first time, that LLLT at 3 or 8u2009J/cm2, but not at 1–2, 4–7, or 9–12u2009J/cm2, induced an analgesic effect on postoperative pain. Naloxone, but not methysergide, blocked the LLLT‐induced anti‐nociceptive effect. Additionally, IL‐1‐β and TNF‐α production significantly decreased after LLLT at 3 or 8u2009J/cm2. Our results suggest that LLLT at 3 or 8u2009J/cm2 primarily modulates the endogenous opioids system and is not directly mediated by serotonergic receptors. Reduction of IL‐1β and TNF‐α may play a role in the antinociceptive action of LLLT. Lasers Surg. Med. 49:844–851, 2017.

Analgesic Effects Elicited by Neuroactive Mediators Injected into the ST 36 Acupuncture Point on Inflammatory and Neuropathic Pain in Mice

The present study evaluates whether the injection of serotonin, acetylcholine, glutamate, bradykinin, histamine, or substance P (SP) into the Zusanli (Stomach 36, ST 36) acupoint can also produce the acupuncture-induced antinociceptive effect on inflammatory or neuropathic pain. In this inxa0vivo experimental study, a total of 450 male Swiss mice were used. Mice were injected with saline or complete Freunds adjuvant (CFA) or subjected to sham or chronic constriction injury (CCI) surgery. After the establishment of the inflammatory (4xa0hours) or the neuropathic pain (3xa0days), the animals (nxa0=xa06) received manual acupuncture, sham acupuncture, or injection of saline, serotonin, acetylcholine, glutamate, bradykinin, histamine, or SP into the ST 36 and were evaluated for up to 24xa0hours. Mechanical threshold was evaluated, and the L4-L6 dorsal root ganglion was used for analysis of the transient receptor potential vanilloid type 1 overexpression. The mice from both the CFA and CCI models treated with manual acupuncture had significant increases in the thresholds for more than 24xa0hours. Sham acupuncture stimulation did not change the thresholds. In the mice injected with each of the mediators, the thresholds were significantly increased for all times in both the CFA and CCI models. Transient receptor potential vanilloid type 1 overexpression in CFA and CCI mice was reduced at all times by injection of serotonin, acetylcholine, or SP but not by injection of glutamate, histamine, or bradykinin. Our data suggestxa0that the neuroactive mediators released by acupuncture-induced tissue injury may contribute to acupuncture-induced analgesia.

Single or Multiple Electroacupuncture Sessions in Nonspecific Low Back Pain: Are We Low-Responders to Electroacupuncture?

The objective of this study was to compare the effects of one or multiple sessions of electroacupuncture (EA) in patients with chronic low back pain. The outcome measures were visual analogxa0score (VAS), pressure pain threshold (PPT), McGill pain questionnaire (MPQ), Roland Morris disability questionnaire (RMDQ), low back skin temperature, surface electromyography of longissimus muscle (contraction/rest) and blood cytokines. After examination (AV0), patients were submitted to EA (2xa0Hz, 30xa0minutes, bilaterally at the SP6, BL23, BL31, BL32, BL33, and BL60) and were revaluated after one week (AV1). Patients with VAS <3 (VAS <3 group, nxa0=xa020) were directed to return after three weeks (AV2). Patients with VAS >3 (VAS >3 group, nxa0=xa020) were submitted to one weekly EA-treatment and revaluated after three weeks (AV2). The VAS <3 group showed a significant reduction in VAS and MPQ and increased PPT in AV1, but not in AV2. No significant differences were found in RMDQ. The VAS >3 group showed reduction in VAS and increased PPT in AV1 and a reduction in MPQ and RMDQ only in AV2. No significant differences were found in electromyography, temperature or cytokines. Thus, despite 2Hz-EA is effective reducing low back pain, some patients only experienced reduced pain intensity and improved functional capacity after full treatment.