European journal of pain : EJP
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Randomized Controlled Trial
Masseter corticomotor excitability is decreased after intramuscular administration of nerve growth factor.
Quantification of motor-evoked potentials (MEPs) can contribute to better elucidate the central modulation of motor pathways in response to nociceptive inputs. The primary aim of this study was to assess the modulatory effects of nerve growth factor (NGF) injection on masseter corticomotor excitability. ⋯ Intramuscular administration of nerve growth factor into masseter muscle causes inhibitory corticomotor plasticity, which likely occurs to prevent further damage and seems associated with lower pain intensity on function.
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Tapentadol is a centrally acting analgesic with μ-agonistic activity combined with noradrenaline reuptake inhibition. Its mechanism of action relies on improvement of descending pain inhibition. In the current study, tapentadol's ability to enhance conditioned pain modulation (CPM, an experimental measure of descending pain inhibition) was evaluated in fibromyalgia patients with absent or reduced CPM responses. ⋯ In this double-blind randomized placebo-controlled trial, we showed that tapentadol significantly enhanced the descending pain inhibition in fibromyalgia patients. Tapentadol-induced pain relief was only present in patients with a normal CNFS.
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Effects from cognitive performance on pain tolerance have been documented, however, sample sizes are small and confounders often overlooked. We aimed to establish that performance on neuropsychological tests was associated with pain tolerance, controlling for salient confounders. ⋯ This paper describes substantial associations between cognitive functioning and cold pressor tolerance in 4,623 participants. Reduced psychomotor speed and poor verbal recall gave greater odds for hand-withdrawal on the cold pressor task. The associations were stronger in older participants, indicating an interaction with age.
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Although the influence of genetics on chronic low back pain (LBP) has been previously examined, few studies have investigated whether the impact of genetic factors on LBP depends on how the condition is assessed. ⋯ Heritability estimates were similar for different low back pain definitions, and therefore not dependent on how chronic low back pain is experienced or assessed, in the same population-based sample.