The journal of pain : official journal of the American Pain Society
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Understanding molecular alterations associated with peripheral inflammation is a critical factor in selectively controlling acute and persistent pain. The present report employs in situ hybridization of the 2 opioid precursor mRNAs coupled with quantitative measurements of 2 peptides derived from the prodynorphin and proenkephalin precursor proteins: dynorphin A 1-8 and [Met5]-enkephalin-Arg6-Gly7-Leu8. In dorsal spinal cord ipsilateral to the inflammation, dynorphin A 1-8 was elevated after inflammation, and persisted as long as the inflammation was sustained. ⋯ These data support the idea that activation of endogenous opioids, notably dynorphin, is a dynamic indicator of persistent pain states in spinal cord and of nerve injury in DRG. PERSPECTIVE: This is a systematic, quantitative assessment of dynorphin and enkephalin peptides and mRNA in dorsal spinal cord and DRG neurons in response to peripheral inflammation and axotomy. These studies form the foundational framework for understanding how endogenous spinal opioid peptides are involved in nociceptive circuit modulation.
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The main cause of trigeminal neuralgia (TN) is compression of a blood vessel at the root entry zone of the trigeminal nerve. However, a neurovascular conflict does not seem to be the only etiology and other mechanisms are implicated in the development of the disease. We hypothesized that TN patients may have distinct protein expression in the CSF. ⋯ The pathophysiological background of the protein alterations found in this study warrants further investigation in future studies. PERSPECTIVE: In this article, cerebrospinal fluid from patients with trigeminal neuralgia was analyzed using in depth shotgun proteomics, revealing 46 differentially expressed proteins compared to controls. Among these, apolipoproteins and proteins involved in the complement system were elevated and significantly over-represented, implying an inflammatory component in the pathophysiology of the disease.
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Spicy-food intake has been shown to affect various human physiological systems and diseases. This study tested the analgesia effect caused by stimulation of a spicy sensation (spicy stimulation) and explored the effect of spicy-food consumption on human basal pain sensitivity. A total of 60 healthy undergraduates were included in the primary study. ⋯ ChiCTR1800015053). PERSPECTIVE: This study directly examined the effects of stimulation of a spicy sensation on adult pain sensitivity and was the first to explore the relationship between long-term spicy-food intake and human pain sensitivity. The results provide evidence for future clinical pain intervention and individualized pain treatment.
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Shoulder surgery is a primary intervention for shoulder pain, yet many individuals experience persistent postoperative pain. Previously, we found individuals categorized as having a high-risk phenotype (comprised of COMT variation and pain catastrophizing) had approximately double the chance of not reaching a 12-month pain recovery criterion. As a means to better understand the development of persistent postoperative shoulder pain, this study advanced our previous work by examining temporal ordering of postoperative shoulder recovery based on potential mediating factors, and expansion of outcomes to include movement-evoked pain and shoulder active range of motion. ⋯ This study introduces potential temporal components and relationships to the development of persistent postoperative shoulder pain, which future studies will confirm and assess for potential therapeutic targets. PERSPECTIVE: This study expands upon postoperative shoulder recovery measures to include movement-evoked pain and depressive symptoms, and provides preliminary indication of temporal ordering to postoperative shoulder recovery for a preidentified high-risk subgroup. Future studies will distinguish temporal components of shoulder surgery that may optimize treatment targets of postoperative recovery.
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The experience of pain relief arises from physiological and psychological factors, and attributes such as the commercial features of analgesic treatments have been shown to influence placebo analgesia by affecting treatment expectations. Therefore, treatment valuation from price information should influence the placebo analgesic effect. This hypothesis was tested in a functional magnetic resonance imaging study in which healthy subjects were enrolled in a 2-day experiment. ⋯ PERSPECTIVE: Treatment with higher price was associated with enhanced placebo analgesia, and this effect was influenced by activities in expectation and reward processing brain areas. The context of value such as medical cost influences cognitive evaluation processes to modulate pain. Our study may help evaluate a patient's preference toward high-priced drugs.