Pain
-
Comparative Study Controlled Clinical Trial
Diminished neurokinin-1 receptor availability in patients with two forms of chronic visceral pain.
Central sensitization and dysregulation of peripheral substance P and neurokinin-1 receptor (NK-1R) signaling are associated with chronic abdominal pain in inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Although positron emission tomography (PET) has demonstrated that patients with injury-related chronic pain have diminished NK-1R availability in the brain, it is unknown whether these deficits are present in IBD and IBS patients, who have etiologically distinct forms of non-injury-related chronic pain. This study's aim was to determine if patients with IBD or IBS exhibit deficits in brain expression of NK-1Rs relative to healthy controls (HCs), the extent to which expression patterns differ across patient populations, and if these patterns differentially relate to clinical parameters. ⋯ BP in a subset of these regions was robustly related to discrete clinical parameters in each patient population. Widespread deficits in NK-1R BP occur in IBD and, to a lesser extent, IBS; however, discrete clinical parameters relate to NK-1R BP in each patient population. This suggests that potential pharmacological interventions that target NK-1R signaling may be most effective for treating distinct symptoms in IBD and IBS.
-
Randomized Controlled Trial Multicenter Study
Daily repetitive transcranial magnetic stimulation of primary motor cortex for neuropathic pain: a randomized, multicenter, double-blind, crossover, sham-controlled trial.
There is little evidence for multisession repetitive transcranial magnetic stimulation (rTMS) on pain relief in patients with neuropathic pain (NP), although single-session rTMS was suggested to provide transient pain relief in NP patients. We aimed to assess the efficacy and safety of 10 daily rTMS in NP patients. We conducted a randomized, double-blind, sham-controlled, crossover study at 7 centers. ⋯ There were no significant cumulative improvements in VAS, SF-MPQ, and BDI. No serious adverse events were observed. Our findings demonstrate that daily high-frequency rTMS of M1 is tolerable and transiently provides modest pain relief in NP patients.
-
In the present meta-analysis, we assessed the efficacy and safety of intravenous administration of dexmedetomidine (DEX) compared with placebo or opioids for acute postoperative pain treatment in adults undergoing surgery. The meta-analysis was performed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement and the recommendations of the Cochrane Collaboration. Randomized controlled trials investigating perioperative administration of DEX were included. ⋯ The comparison of DEX vs opioids for postoperative pain treatment is less clear due to limited data. The most common adverse event was intraoperative bradycardia after DEX administration. Therefore cautions in patients at risk are warranted, and large trials focusing on long-term outcomes after intraoperative DEX use are needed.
-
Estrogen status and psychological stress contribute to the expression of several chronic pain conditions including temporomandibular muscle and joint disorders (TMJD). Sensory neurons that supply the temporomandibular joint (TMJ) region terminate in laminae I and V of the spinal trigeminal nucleus (Vc/C1-2 region); however, little is known about lamina-specificity and environmental influences on the encoding properties of TMJ brainstem neurons. To test the hypothesis that Vc/C1-2 neurons integrate both interoceptive and exteroceptive signals relevant for TMJ nociception, we recorded TMJ-evoked activity in superficial and deep laminae of ovariectomized rats under high and low estradiol (E2) and stress conditions. ⋯ By contrast, FS conditioned rats displayed increased background firing and TMJ-evoked activity of neurons in deep, but not superficial, laminae independent of E2 status. FS also enhanced TMJ-evoked masseter muscle activity and suggested the importance of deep dorsal horn neurons in mediating evoked jaw muscle activity. In conclusion, E2 status and psychophysical stress play a significant role in modifying the encoding properties of TMJ-responsive medullary dorsal horn neurons with a marked lamina-specificity.
-
Chronic musculoskeletal complaints (MSCs) are among the major health problems, and cross-sectional studies suggest an association between smoking and MSCs. The causal relationship, however, is not known. The present study is designed to assess the association between smoking and chronic MSCs, and is based on data from a large longitudinal cohort study of all inhabitants ⩾20years in Nord-Trøndelag County (Helse Undersøkelsen i Nord-Trøndelag -HUNT), conducted in 1995-97 (HUNT 2) and 2006-08 (HUNT 3). ⋯ The results show that smoking at baseline represents a 20% increased risk (IRR=1.20, 95% CI 1.14-1.27, P=0.0001) for chronic MSCs at follow-up. The risk for chronic MSCs by daily smoking decreased with increasing age up to 50years; after this, there was no significant association. The results show that modifiable risk factors like smoking should be included in public health intervention programs for MSCs.