European journal of pain : EJP
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Randomized Controlled Trial
Temporal summation of pressure pain during muscle hyperalgesia evoked by nerve growth factor and eccentric contractions.
Nerve growth factor (NGF) has a key role in the generation and potentiation of pain. Its centrally sensitizing effects may facilitate pain responses to noxious stimulus. This study assessed (1) the influence of NGF on delayed onset muscle soreness (DOMS) in shoulder muscles; and (2) the temporal summation of pressure pain during hyperalgesia induced by NGF and DOMS. ⋯ The NGF injected side had higher pain ratings during temporal summation at 1s ISI compared with the contralateral side 24h after injections. Intramuscular administration of NGF intensified the DOMS responses, evoking facilitated temporal summation. Central as well as peripheral sensitization mechanisms may play a role in the facilitation.
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The diagnosis Complex Regional Pain Syndrome type I (CRPS-I) is based on clinical symptoms, including motor symptoms. Histological changes in muscle tissue may be present in the chronic phase of CRPS-I. Aim of this study was to analyze skeletal muscle tissue from amputated limbs of patients with CRPS-I, in order to gain more insight in factors that may play a role in changes in muscles in CRPS-I. ⋯ Intrinsic and extrinsic muscles were affected equally. Our findings show that in the chronic phase of CRPS-I extensive changes can be seen in muscle tissue, not related to duration of CRPS-I symptoms. Signs of neurogenic myopathy were present in five patients.
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Chronic pelvic pain (CPP) in women is a long-lasting condition. ⋯ At a 3 year follow-up, improvement in pain intensity in women with CPP was not associated with baseline pain appraisals and coping strategies. A reduction in catastrophizing was related to better outcome in the long term.
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The aim of this study was to determine the analgesic effect of gabapentin and tiagabine - two antiepileptic drugs, administered alone and in combination at the fixed-ratio of 1:1, in two phases of the formalin test in mice. Log-probit analysis was used to evaluate dose-response effects and calculate the ED(50) values for gabapentin, tiagabine, and their combination at the fixed-ratio of 1:1 in the phases I and II of the formalin test in mice. The types of interactions between both antiepileptic drugs were characterized using the isobolographic analysis. ⋯ With isobolography, the ED(50 mix) values at the fixed-ratio combination of 1:1 were 7.30 mg/kg (phase I) and 0.48 mg/kg (phase II), indicating both additive and supra-additive (synergistic) interactions between gabapentin and tiagabine in the formalin test in mice. In conclusion, the combination of gabapentin with tiagabine at the fixed-ratio of 1:1 exerted additive interaction in the phase I and synergistic interaction in the phase II of the formalin test in mice. If the results from this study could be extrapolated to clinical settings, the combination of tiagabine with gabapentin might be beneficial in the pain relief in humans.
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Loss of function is usually considered the major consequence of spinal cord injury (SCI). However, pain severely compromises the quality of life in nearly 70% of SCI patients. The principal aim of this study was to assess the contribution of Tumor necrosis factor alpha (TNF-alpha) to SCI pain. ⋯ Furthermore, minocycline decreased the expression of noxious-stimulation-induced c-Fos, suggesting an effect on evoked neuronal activity. This study demonstrates that TNF-alpha plays an important role in the establishment of neuropathic pain following SCI, seemingly dependent on microglial activation. Pharmacological targeting of TNF-alpha may offer therapeutic opportunities for treating SCI pain.