Pain
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Bone cancer pain has been reported to have unique mechanisms and is resistant to morphine treatment. Recent studies have indicated that neuron-restrictive silencer factor (NRSF) plays a crucial role in modulating the expression of the μ-opioid receptor (MOR) gene. The present study elucidates the regulatory mechanisms of MOR and its ability to affect bone cancer pain. ⋯ Furthermore, genetically knocking down NRSF with antisense oligodeoxynucleotide rescued the expression of MOR and potentiated the systemic morphine analgesia. The present results suggest that in sarcoma-induced bone cancer pain, NRSF-induced downregulation of MOR is involved in the reduction of morphine analgesia. Epigenetically, up-regulation of MOR could substantially improve the effect of system delivery of morphine.
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The melastatin-related transient receptor potential (TRP) channel TRPM3 is a nonselective cation channel expressed in nociceptive neurons and activated by heat. Because TRPM3-deficient mice show inflammatory thermal hyperalgesia, pharmacological inhibition of TRPM3 may exert antinociceptive properties. Fluorometric Ca influx assays and a compound library containing approved or clinically tested drugs were used to identify TRPM3 inhibitors. ⋯ Primidone blocked PregS-induced Cai influx through TRPM3 by allosteric modulation and reversibly inhibited atypical inwardly rectifying TRPM3 currents induced by coapplication of PregS and clotrimazole. In vivo, analgesic effects of low doses of primidone were demonstrated in mice, applying PregS- and heat-induced pain models, including inflammatory hyperalgesia. Thus, applying the approved drug at concentrations that are lower than those needed to induce anticonvulsive effects offers a shortcut for studying physiological and pathophysiological roles of TRPM3 in vivo.
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Randomized Controlled Trial Multicenter Study
Follow-up at the corrected age of 24 months of preterm newborns receiving continuous infusion of fentanyl for pain control during mechanical ventilation.
The neurodevelopmental impact of fentanyl given to preterm newborns for pain control is still unknown. The aim of this study was to assess the neurodevelopmental impact of 2 regimens of fentanyl administration by a prospective follow-up evaluation. In our previous multicenter, double-blind, randomized controlled trial, 131 mechanically ventilated newborns (gestational age ≤32 weeks) were randomized to fentanyl (continuous infusion of fentanyl + open label boluses of fentanyl) or placebo (continuous infusion of placebo + open label boluses of fentanyl). ⋯ After adjustment for clinical confounders (gestational age, CRIB score, and sex) only eye-hand co-ordination was associated with fentanyl infusion. This study demonstrates that continuous infusion of fentanyl in very preterm infants, given at 1 mcg·kg·h during mechanical ventilation, is associated with a significant decrease in eye and hand co-ordination skills. Longer follow-up is needed to evaluate the impact on future motor, cognitive, and behavioral functions.
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Strategies directed at the prevention of disabling pain have been suggested as a public health priority, making early identification of youth at risk for poor outcomes critical. At present, limited information is available to predict which youth presenting with acute pain are at risk for persistence. The aims of this prospective longitudinal study were to identify biopsychosocial factors in the acute period that predict the transition to persistent pain in youth with new-onset musculoskeletal (MSK) pain complaints. ⋯ Results revealed approximately 35% of youth had persistent pain at 4-month follow-up, with persistent pain predicted by poorer conditioned pain modulation and female sex. Higher depressive symptoms at T1 were associated with higher pain-related disability and poorer QOL at T2. Findings highlight the roles of depressive symptoms and pain modulation in longitudinally predicting pain persistence in treatment-seeking youth with acute MSK pain and suggest potential mechanisms in the transition from acute to chronic MSK pain in children and adolescents.