European journal of pain : EJP
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The aim of this study was to explore the nociceptive system of patients affected by trigeminal neuralgia (TN) secondary to documented vascular contact who underwent microvascular decompression. For that purpose, we used the classical trigeminal reflexes and the trigeminal laser-evoked potentials (tLEPs) before and after surgery, in order to verify any possible change after decompression and determine if there was any correlation between the neurophysiological parameters and the clinical outcome. ⋯ This study demonstrates that TN caused by trigeminovascular compression may be related to Aδ fibres impairment, and tLEPs are more sensitive than conventional trigeminal reflexes to reveal small fibre dysfunction and to monitor the post-surgical outcome in these patients.
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Previous data showed that, in rats, anti-migraine drugs (triptans, olcegepant) significantly reduced mechanical allodynia induced by infraorbital nerve (ION) ligation but not that evoked by sciatic nerve (SN) ligation. Whether this also occurs with MK-8825, a novel anti-migraine drug also acting through CGRP receptor blockade (but chemically unrelated to olcegepant) was tested in the present study, which also investigated possible anti-neuroinflammatory effects of this drug. ⋯ These data further support the idea that CGRP receptor blockade might be a valuable approach to alleviate trigeminal, but not spinal, neuropathic pain through, at least partly, an inhibitory effect on neuropathic pain-associated increase in NO production in trigeminal ganglion.
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Pain is a common and highly debilitating complication for cancer patients significantly compromising their quality of life. Cancer-induced bone pain involves a complex interplay of multiple mechanisms including both inflammatory and neuropathic processes and also some unique changes. Strong opioids are a mainstay of treatments but side effects are problematic and can compromise optimal pain control. Tapentadol is a novel dual-action drug, both stimulating inhibitory μ-opioid receptors (MOR) and mediating noradrenaline reuptake inhibition (NRI) leading to activation of the inhibitory α-2 adrenoceptor. It has been demonstrated to treat effectively both acute and chronic pain. We here demonstrate the efficacy in a model of cancer-induced bone pain. ⋯ These findings add to the mechanistic understanding of cancer-induced bone pain and support the sparse clinical data indicating a possible use of the drug as a therapeutic alternative for cancer patients with metastatic pain complication.
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Previous studies have indicated that the startle reflex is potentiated by phasic, but not by tonic, heat pain, although the latter is seen as more strongly associated with emotional responses and more similar to clinical pain. The threat value of pain might be a decisive variable, which is not influenced alone by stimulus duration. ⋯ Our results suggest that subjective threat might indeed be decisive for the action of pain on startle; the threat level appears not only influenced by actual expectations but also by previous experiences with pain as threatening or not.
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Recent research suggests that anxiety sensitivity (AS) may be a critical factor in the maintenance of chronic pain. Converging lines of evidence also propose a relationship between AS and fear of pain (FOP) that may result from interoceptive fear conditioning in interoceptively biased individuals. While some AS and FOP research has been carried out in adults, literature exploring this relationship is sparse in clinical paediatric populations. ⋯ These results provide evidence for the pivotal role of AS in the paediatric chronic pain model. The findings of this study further emphasize the application of the fear-avoidance model in children and provide new evidence for the critical role of AS in a paediatric headache population.