European journal of pain : EJP
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Dopamine (DA) is thought to be important to local hippocampal networks integrity during spatial working memory (sWM) processing. Chronic pain may contribute to deficient dopaminergic signalling, which may in turn affect cognition. However, the neural mechanisms that determine this impairment are poorly understood. Here, we evaluated whether the sWM impairment characteristic of animal models of chronic pain is dependent on DA D2 receptor (D2r) activity. ⋯ This study provides new insights into the role of D2r in the manifestation of pain-related sWM deficits. Our findings support that selective blockade of D2r produces a significant decrease in intrahippocampal connectivity mediated by theta-oscillations, and amplifies pain-related sWM deficits. These results suggest that further characterization of intrahippocampal dopaminergic modulation may be clinically relevant for the understanding of cognitive impairments that accompanies nociceptive stressful conditions.
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Fine-grained observational approaches to pain assessment (e.g. the Facial Action Coding System; FACS) are used to evaluate pain in individuals with and without dementia. These approaches are difficult to utilize in clinical settings as they require specialized training and equipment. Easy-to-use observational approaches (e.g. the Pain Assessment Checklist for Limited Ability to Communicate-II; PACSLAC-II) have been developed for clinical settings. Our goal was to compare a FACS-based fine-grained system to the PACSLAC-II in differentiating painful from non-painful states in older adults with and without dementia. ⋯ Examining older adults with and without dementia, a brief observational clinical approach was found to be valid and accounted for more variance in differentiating pain-related and non-pain-related states than did a detailed time-consuming fine-grained approach.
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Prostaglandin E2 (PGE2) enriched in inflamed tissues contributes to chronic pain by sensitizing nociceptive dorsal root ganglion (DRG) neurons (nociceptors). Of four PGE2 receptors (EP1-4), EP4 plays a major role in PGE2-induced nociceptor sensitization. We have previously reported that PGE2 or EP4 agonists stimulated EP4 externalization in cultured DRG neurons and this event contributes to nociceptor sensitization. However, the signalling transduction events governing this event remain unknown. ⋯ This study adds mechanistic information regarding signalling transduction events involved in agonist-induced EP4 cell surface trafficking. EP4 and EP2 (to lesser extent) receptors, extra- and intracellular Ca++ , CaKMII, cAMP, PKA, PKC, PKCε, PLC, MAPK, PI3K and Akt are involved in this event. Agonist-induced EP4 externalization contributes to enhanced nociceptor sensitization.
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Low back pain is common in the general population and in individuals with primary headaches. We assessed the relative frequency of self-reported back pain in persons with and without primary headaches and examined pain sensitivity. ⋯ We found that back pain has high relative frequency in individuals with CH followed EH and no headache. Back pain is associated with low cephalic and extracephalic PPTs in individuals with CH. Central sensitization may be a substrate or consequence of this comorbidity of back pain and CH.
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The Pain Coping Questionnaire (PCQ), the first validated pain coping measurement developed specifically for children, has lacked proper validation in Finnish. The original PCQ by Reid et al. (Pain 1998; 76; 83-96) comprises eight-first-order and three higher-order scales. The aim herein was to determine the factor structure and validity of the Finnish PCQ translation in Finnish children. ⋯ This study showed both culturally and statistically satisfactory factor structure of PCQ in the Finnish translation. This result supports reliability and validity of the PCQ in the national use in the future. The result shows that the PCQ is a reliable method to be used in different linguistic and cultural surroundings and, thus, encourages using it in various countries. The data consist of two patient groups, adolescents with JIA and musculoskeletal pain. Pain and specifically coping with pain are important aspects of clinical work. A valid pain coping scale may enhance distinguishing vulnerable pain coping style in children and adolescent before pain becomes chronic.