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Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Dec 2022This study aimed to investigate whether the microglia in the spinal trigeminal nucleus caudal part (Sp5C) were activated in a rat model of trigeminal neuralgia and to...
OBJECTIVES
This study aimed to investigate whether the microglia in the spinal trigeminal nucleus caudal part (Sp5C) were activated in a rat model of trigeminal neuralgia and to explore whether the activation level of microglia is consistent with maxillofacial pain level.
METHODS
Chronic constriction injury of trigeminal nerve (CCI) was induced by partial ligation of infraorbital nerve (IoN) in rats. The behavioral change of rats observed at D1, D5, D10, D15, and D30 days post-surgery and the change of pain threshold were detected with electronic Von Frey filaments served as an evaluation index of maxillofacial pain. Weight change was measured by weighing. Ionized calcium binding adaptor molecule-1 (Iba-1) expression level of Sp5C at each time point was detected, and three microglia morphological categories were analyzed by immunohistochemical staining.
RESULTS
The changes of behavioral and pain threshold suggested the maxillofacial pain level first increased and then decreased post-surgery in the IoN-CCI group. Both the expressions of Iba-1 and proportion of ameboid morphology in ipsilateral Sp5C increased from D1 and reached their peaks in D10 and D5, respectively. Then, they recovered nearly to the same level with contralateral Sp5C on D30. This trend was consistent with the maxillofacial change.
CONCLUSIONS
The model of trigeminal neuralgia in rats constructed by partial ligation of infraorbital nerve can induce the activation of microglia in Sp5C, and the activation level is consistent with maxillofacial pain, which reached its peak at around D10 post-surgery.
Topics: Rats; Animals; Trigeminal Neuralgia; Rats, Sprague-Dawley; Microglia; Pain Threshold; Pain
PubMed: 36416315
DOI: 10.7518/hxkq.2022.06.003 -
Scandinavian Journal of Pain Jul 2017
Topics: Humans; Low Back Pain; Movement; Pain Threshold
PubMed: 28850399
DOI: 10.1016/j.sjpain.2017.03.008 -
Pain Jun 2023Stress plays a major role in the symptom burden of oncology patients and can exacerbate cancer chemotherapy-induced peripheral neuropathy (CIPN), a major adverse effect...
Stress plays a major role in the symptom burden of oncology patients and can exacerbate cancer chemotherapy-induced peripheral neuropathy (CIPN), a major adverse effect of many classes of chemotherapy. We explored the role of stress in the persistent phase of the pain induced by oxaliplatin. Oxaliplatin induced hyperalgesic priming, a model of the transition to chronic pain, as indicated by prolongation of hyperalgesia produced by prostaglandin E 2 , in male rats, which was markedly attenuated in adrenalectomized rats. A neonatal handling protocol that induces stress resilience in adult rats prevented oxaliplatin-induced hyperalgesic priming. To elucidate the role of the hypothalamic-pituitary-adrenal and sympathoadrenal neuroendocrine stress axes in oxaliplatin CIPN, we used intrathecally administered antisense oligodeoxynucleotides (ODNs) directed against mRNA for receptors mediating the effects of catecholamines and glucocorticoids, and their second messengers, to reduce their expression in nociceptors. Although oxaliplatin-induced hyperalgesic priming was attenuated by intrathecal administration of β 2 -adrenergic and glucocorticoid receptor antisense ODNs, oxaliplatin-induced hyperalgesia was only attenuated by β 2 -adrenergic receptor antisense. Administration of pertussis toxin, a nonselective inhibitor of Gα i/o proteins, attenuated hyperalgesic priming. Antisense ODNs for Gα i 1 and Gα o also attenuated hyperalgesic priming. Furthermore, antisense for protein kinase C epsilon, a second messenger involved in type I hyperalgesic priming, also attenuated oxaliplatin-induced hyperalgesic priming. Inhibitors of second messengers involved in the maintenance of type I (cordycepin) and type II (SSU6656 and U0126) hyperalgesic priming both attenuated hyperalgesic priming. These experiments support a role for neuroendocrine stress axes in hyperalgesic priming, in male rats with oxaliplatin CIPN.
Topics: Rats; Male; Animals; Hyperalgesia; Rats, Sprague-Dawley; Oxaliplatin; Pain Threshold; Chronic Pain
PubMed: 36729863
DOI: 10.1097/j.pain.0000000000002828 -
Pain Research & Management 2015To evaluate the number of tender points, pressure pain threshold and presence of fibromyalgia among women with or without dyspareunia.
OBJECTIVE
To evaluate the number of tender points, pressure pain threshold and presence of fibromyalgia among women with or without dyspareunia.
METHODS
The present cross-sectional study included 40 patients with dyspareunia and 30 healthy controls. The participants were asked if they had engaged in sexual intercourse during the previous four weeks, and dyspareunia was rated from 0 to 3 based on the Marinoff Dyspareunia Scale. A pressure algometer (dolorimeter) was used to measure the pressure pain threshold. Fibromyalgia was diagnosed based on the 1990 American College of Rheumatology criteria. The depression status of the participants was assessed using the Beck Depression Inventory.
RESULTS
No statistically significant difference was found with regard to age, body mass index, habits (alcohol use and smoking), educational status and occupational status between the two groups. Total myalgic score, total control score and tender point mean pain threshold were significantly lower in the group with dyspareunia. The number of tender points was significantly higher in patients with dyspareunia. The mean Beck Depression Inventory score was 14.7±8.4 in the dyspareunia group compared with 11.2±7.1 in the control group. Five (12.5%) of the patients with dyspareunia were diagnosed with fibromyalgia, whereas no patients in the control group were diagnosed with fibromyalgia. There was no significant difference between the two groups with regard to the presence of fibromyalgia.
CONCLUSION
The finding of lower pressure pain thresholds and a higher number of tender points among patients with dyspareunia suggests that these patients may have increased generalized pain thresholds. Additional studies involving a larger number of patients are required to investigate the presence of central mechanisms in the pathogenesis of dyspareunia.
Topics: Adult; Case-Control Studies; Cross-Sectional Studies; Depression; Dyspareunia; Female; Fibromyalgia; Humans; Pain; Pain Measurement; Pain Threshold; Pressure; Psychiatric Status Rating Scales; Severity of Illness Index
PubMed: 25996766
DOI: 10.1155/2015/302404 -
PeerJ 2022Monitoring of pain threshold is the basis for verification of the effectiveness of therapy or assessment of the patient's condition. This study aimed to determine the...
BACKGROUND
Monitoring of pain threshold is the basis for verification of the effectiveness of therapy or assessment of the patient's condition. This study aimed to determine the pain threshold of selected superficial muscles of the back taking into account trigger point activity in young and healthy males and females, with the evaluation of intrarater reliability of algometric measurements.
MATERIAL AND METHODS
The study examined 30 young adult participants (15 males and 15 females) aged 26.23 ± 3.21, and BMI of 23.80 ± 3.43. The Pain Test FPX Algometer (Wagner) was used for the study. Trigger points on the levator scapulae and trapezius muscles (superior and inferior portion) on both sides were examined. It was also verified whether the trigger points studied are active or inactive. Furthermore, an author's survey questionnaire was used.
RESULTS
Within the trigger points of the right ( = 0.04) and left ( = 0.02) superior trapezius muscle and the left ( = 0.04) levator scapulae muscle, the pain threshold values were higher in the male group. There was a statistically significantly higher number of active trigger points in the female group compared to that in the male group (2.49 ± 1.51 . 1.07 ± 1.16, respectively), = 0.01. For all muscles tested, mean pain threshold values were significantly higher for inactive trigger points. A greater number of active trigger points is associated with lower pain thresholds at these points (left: the superior trapezius, = -0.597, the inferior trapezius, = -0.609; the levator scapulae, = -0.746; right: the superior trapezius, = -0.610, the inferior trapezius, = -0.604; the levator scapulae, = -0.747). The evaluation of the intrarater reliability showed excellent agreement between the first and second measurements, ICC > 0.987 for all examined trigger points.
CONCLUSIONS
(1) Women who reported pain more than once a week in the studied muscles showed a greater number of active trigger points. (2) A greater number of active trigger points in female is related to a lower pain threshold (which is associated with greater pain sensitivity) in female than in male. (3) A sample size of 30 people seems sufficient to detect variations in the pain threshold at active and inactive trigger points of selected back muscles, especially when the frequency of occurrence of both types of points is comparable.
Topics: Humans; Male; Female; Young Adult; Pain Threshold; Trigger Points; Reproducibility of Results; Myofascial Pain Syndromes; Pain; Muscle, Skeletal
PubMed: 35178293
DOI: 10.7717/peerj.12780 -
The Journal of Pain Dec 2016Although clinical studies suggest depressed patients may be more vulnerable to pain, experimental research is equivocal. This meta-analysis aimed to clarify whether... (Meta-Analysis)
Meta-Analysis Review
UNLABELLED
Although clinical studies suggest depressed patients may be more vulnerable to pain, experimental research is equivocal. This meta-analysis aimed to clarify whether depression is associated with altered pain perception in response to noxious stimulation and to identify factors that might influence this association. A search of major electronic databases was conducted to identify experimental studies investigating pain response in depressed participants versus healthy control participants using established pain outcome measures. Random effects meta-analysis of standardized mean differences was conducted on data from 32 studies (N = 1,317). For high-intensity noxious stimulation, overall pain tolerance was similar across depressed and control groups (Hedges g = .09, P = .71, studies = 10). For low-intensity stimulation, a small, but statistically significant higher mean sensory threshold (g = .35, P = .01, studies = 9) and pain threshold (g = .32, P = .02, studies = 25) was observed in depressed participants, suggesting diminished pain. However, considerable heterogeneity in the direction and magnitude of effects was observed, indicating a likely condition-specific effect of depression on pain. Subgroup analysis found that pain threshold/tolerance was increased in depression for exteroceptive (cutaneous) stimulation but decreased for interoceptive (ischemic) stimulation, but that substantial heterogeneity remained. Overall, results provide some support for altered pain processing in depression, but suggest this link is dependent upon modality and additional, unidentified factors.
PERSPECTIVE
This meta-analysis of experimental studies suggests potential effects of depression on pain perception are variable and likely to depend upon multiple factors. The contrasting pattern for ischemic versus other noxious stimuli suggests that stimulus modality is a key factor, which could help explain discrepancies across clinical and experimental findings.
Topics: Depression; Humans; Pain Perception; Pain Threshold
PubMed: 27589910
DOI: 10.1016/j.jpain.2016.08.007 -
Human Brain Mapping Dec 2020Many studies suggested shared psychological and neural representations for first-hand physical pain and empathy for others' pain, both of which depend strongly upon...
Many studies suggested shared psychological and neural representations for first-hand physical pain and empathy for others' pain, both of which depend strongly upon top-down controlled mechanisms such as attention. This study aimed to assess the interindividual variation in first-hand physical pain and empathy for pain, and whether their relationship is dependent upon attention. We recruited participants exhibiting high and low sensitivity to first-hand pain (HPS and LPS), and adopted pain empathy paradigms involving attention directed toward or withdrawn from pain of another. Relative to the LPS group, participants in the HPS group estimated greater pain intensity experienced by others, felt greater unpleasantness when viewing others in pain, and exhibited greater sensitivity in discriminating others' pain. Electroencephalographic data showed that when attention was directed toward others' pain, only participants in the HPS group exhibited significant pain empathic effects on the N1 component of event-related potentials and on the α-oscillation response. These empathic neural responses mediated the linkage between first-hand pain sensitivity and empathic behavioral responses. Nevertheless, empathic responses were comparable between two groups when attention was withdrawn from others' pain. These results demonstrate a shared sensitivity to first-hand pain and empathy for pain provided that attention is directed toward pain.
Topics: Adult; Electric Stimulation; Electroencephalography; Empathy; Evoked Potentials; Female; Humans; Male; Nociceptive Pain; Pain Measurement; Pain Threshold; Social Perception; Young Adult
PubMed: 32761989
DOI: 10.1002/hbm.25160 -
Scientific Reports Sep 2022Transcutaneous medium-frequency alternating electrical current is defined as an alternating current between 1 and 10 kHz and is capable of producing an instant,...
Transcutaneous medium-frequency alternating electrical current is defined as an alternating current between 1 and 10 kHz and is capable of producing an instant, reversible block. This study aims to evaluate the efficacy of sensory perception and force production of the index and middle finger after transcutaneous medium-frequency alternating electrical current stimulation of the distal median nerve. A single-center prospective interventional cohort study was conducted in adult healthy volunteers at the Jessa Hospital, Hasselt, Belgium. Two different electrodes (PALS & 3M) were placed on the distal median nerve, which was located using a Sonosite X-Porte Ultrasound transducer, with the first electrode being placed on the skin at the level of the transverse carpal ligament and the second electrode 7 cm proximally to the first electrode. The tactile sensation was evaluated with Semmes-Weinstein monofilament test and sensation of pressure/pain was evaluated with an algometer. Peak force production was assessed with an electronic dynamometer. All measurements were performed at baseline and tMFAEC stimulation frequencies of 2 and 10 kHz in a randomized manner. Statistical analysis was performed with a one-way ANOVA with repeated measures test or a Friedman rank sum test, followed by the Wilcoxon signed rank test adjusted with Bonferroni correction. A p-value < 0.05 was considered statistically significant. From 9 to 13th of April 2021, 25 healthy volunteers were included in the Jessa Hospital, Hasselt, Belgium. A statistically significant reduction in tactile sensation during 2 kHz and 10 kHz stimulation compared to baseline was observed (2.89 ± 0.22 (PALS2); 3.35 ± 0.25 (3M2) and 2.14 ± 0.12 (PALS10); 2.38 ± 0.12 (3M10) versus - 1.75 ± 0.09 (baseline), p < 0.0001). 3M electrodes showed a tendency towards the elevation of pressure pain threshold compared to baseline. No significant difference in mean peak forces of the index and middle fingers after transcutaneous medium-frequency alternating electrical current stimulation with 2 and 10 kHz was found. This study demonstrates that transcutaneous medium-frequency alternating electrical current stimulation on the distal median nerve inhibits tactile sensory nerve activity in the index and middle finger when stimulation of 2 kHz and, to a lesser extent, 10 kHz was applied. A reduction of motor nerve activity was not observed but force production measurements may be prone to error.Trial registration: clinicaltrials.gov on 01/04/2021. NCT-Number: NCT04827173.
Topics: Adult; Cohort Studies; Humans; Median Nerve; Pain; Pain Threshold; Prospective Studies; Transcutaneous Electric Nerve Stimulation
PubMed: 36050354
DOI: 10.1038/s41598-022-18974-3 -
Scandinavian Journal of Pain Jul 2020Background and aims Evidence for analgesic effects of oral alcohol consumption on heat pain has recently been documented in a placebo-controlled, randomized and... (Randomized Controlled Trial)
Randomized Controlled Trial
Background and aims Evidence for analgesic effects of oral alcohol consumption on heat pain has recently been documented in a placebo-controlled, randomized and double-blind design. We aimed at further investigating these effects and now set the focus on pain threshold and the ratings of supra-threshold pain to cover most of the pain range. Moreover, we now firstly evaluated sex differences in these effects. Methods We investigated 41 healthy participants (22 females) in a randomized, double-blind and placebo-controlled design and targeted two different moderate breath-alcohol levels of 0.06% and 0.08%. Before and after an alcoholic or placebo drink, contact heat was applied at the forearm. Subjects evaluated pain threshold (method of adjustment) and rated pain intensity and pain unpleasantness of supra-threshold stimuli (intensity: threshold +3 °C; duration: 5 s). Results Analgesic effects taking the form of increased pain thresholds were found after both alcohol doses, surprisingly with more pronounced effects for the lower dose. While the high alcohol dose exerted small analgesic effects on pain intensity ratings (i.e. decrease), slightly increased ratings of pain intensity and pain unpleasantness after the low alcohol dose rather suggest pain enhancement. Alcohol did not affect intensity vs. unpleasantness ratings differentially. We found no evidence for sex differences in any of these effects. Conclusions Overall, acute alcohol effects on pain were subtle. Our findings suggest that while low alcohol doses already exert analgesic effects on pain threshold, stronger doses are required for pain reduction on supra-threshold pain levels. Furthermore, sex differences could not be detected within our experimental paradigm but should be further explored in future research. Implications Analgesic effects of sub-toxic alcohol doses - as normally occurring during social drinking - might be weak; however, susceptibility to pain relieving effects of alcohol might be a risk factor for the use of alcohol as self-medication in acute pain states.
Topics: Administration, Oral; Adult; Alcohol Drinking; Analgesics; Dose-Response Relationship, Drug; Double-Blind Method; Ethanol; Female; Humans; Male; Middle Aged; Pain; Pain Threshold; Reaction Time; Surveys and Questionnaires
PubMed: 32755104
DOI: 10.1515/sjpain-2019-0144 -
Chiropractic & Manual Therapies Feb 2021Pain hypersensitivity can be assessed using Quantitative Sensory Testing (QST) and is associated with persistent low back pain. Spinal manipulation appears to modify... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Pain hypersensitivity can be assessed using Quantitative Sensory Testing (QST) and is associated with persistent low back pain. Spinal manipulation appears to modify pain hypersensitivity, and this could function as one mechanism leading to clinical improvements. In the current study, we applied a comprehensive QST battery to assess pain sensitivity in a cohort of low back pain patients before and after spinal manipulation to improve our understanding of the association between QST and clinical improvements. This study addresses two questions: Are clinical improvements following spinal manipulation in low back pain patients contingent on pain hypersensitivity, and does pain sensitivity change following spinal manipulation?
METHODS
We performed a secondary analysis of data from a randomized clinical trial. One hundred and thirty-two participants with persistent LBP were treated with spinal manipulation four times over two weeks. Patient-reported outcomes and QST were assessed at baseline, after the fourth spinal manipulation session, and 14-days later. The clinical outcomes were changes in low back pain intensity and disability. Using latent profile analysis, we categorized the participants into clusters depending on their baseline QST scores. We used linear mixed models to examine the association between clusters and changes in patient-reported outcomes and QST.
RESULTS
Two clusters emerged: a Sensitized and a Not sensitized. The former had significantly lower regional pressure and thermal pain thresholds, remote pressure pain tolerance, and lower inhibitory conditioned pain modulation than the Not sensitized group. However, we only found between-cluster differences for regional pressure pain threshold following spinal manipulation. Thus, the clusters were not associated with patient-reported pain and disability changes or the remaining QST outcomes.
CONCLUSIONS
We report that the baseline QST profile was not associated with clinical improvements following spinal manipulation. We did observe a substantial change for regional pressure pain threshold, which suggests that any effect of spinal manipulation on pain sensitivity is most likely to be observed as changes in regional, mechanical pain threshold. However, the mechanism that invokes clinical improvement and pain sensitivity changes appear distinct. Due to methodological caveats, we advise caution when interpreting the results.
TRIAL REGISTRATION
Clinical.Trial.gov identifier: NCT04086667 , registered 11 September 2019 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04086667.
Topics: Adult; Cluster Analysis; Disability Evaluation; Female; Humans; Low Back Pain; Male; Manipulation, Spinal; Middle Aged; Pain Measurement; Pain Threshold; Patient Reported Outcome Measures
PubMed: 33627163
DOI: 10.1186/s12998-021-00367-4