Pain
-
The objective of this study is to identify subgroups of patients with non-specific neck pain who are more likely to benefit from either physiotherapy, spinal manipulation therapy, or usual care, on the short- and long-term. Data of three recently finished randomised controlled trials, with similar design and setting, were combined. The combined study population consisted of 329 patients with non-specific neck pain in an adult (18-70years) primary care population in the Netherlands. ⋯ The analysis revealed three predictors for recovery of which the effect is modified by treatment: pain intensity (0-10 scale) in the short-term model, age and (no) accompanying low back pain in the long-term model. With these predictors a clinically relevant improvement in recovery rate (up to 25% improvement) can be established in patients receiving a tailored instead of a non-advised treatment. In conclusion we identified three characteristics that facilitate a deliberate treatment choice, to optimise benefit of treatment in patients with non-specific neck pain: age, pain intensity, and (no) accompanying low back pain.
-
Comparative Study
The role of heterosynaptic facilitation in long-term potentiation (LTP) of human pain sensation.
Long-term potentiation (LTP) of nociceptive synaptic transmission induced by high-frequency electrical stimulation (HFS) predominantly modulates natural somatosensory perceptions mediated by Adelta- and Abeta-fibers in humans at the site of conditioning stimulation. The relative contribution of homo- and heterosynaptic mechanisms underlying those perceptual changes remained unclear. We therefore compared changes of the somatosensory profile between a conditioned skin site (homotopic zone) and an area adjacent to conditioning HFS (heterotopic zone). ⋯ Moreover, a small decrease of thresholds to blunt pressure was found at both zones (p<0.05). Pain summation (windup ratio), mechanical detection threshold as well as vibration detection threshold remained unchanged. Because none of the changes in sensory parameters was unique for the site of conditioning stimulation, these data suggest that heterosynaptic interactions are the predominant mechanism of LTP in nociceptive pathways.
-
Palmitoylethanolamide (PEA) is an endogenous lipid that is thought to be involved in endogenous protective mechanisms activated as a result of stimulation of inflammatory response. In spite of the well demonstrated anti-inflammatory properties of PEA, its involvement in controlling pain pathways still remains poorly characterized. On this basis, we tested the efficacy of PEA in vivo against a peculiar persistent pain, such as neuropathic one. ⋯ The results indicated that CB(1), PPARgamma and TRPV1 receptors mediated the antinociception induced by PEA, suggesting that the most likely mechanism might be the so-called "entourage effect" due to the PEA-induced inhibition of the enzyme catalyzing the endocannabinoid anandamide (AEA) degradation that leads to an enhancement of its tissue levels thus increasing its analgesic action. In addition, the hypothesis that PEA might act through the modulation of local mast cells degranulation is sustained by our findings showing that PEA significantly reduced the production of many mediators such as TNFalpha and neurotrophic factors, like NGF. The findings presented here, in addition to prove the beneficial effects of PEA in chronic pain, identify new potential targets for analgesic medicine.
-
Accumulating evidence points to significant cognitive disruption in individuals with Fibromyalgia Syndrome (FMS). This study was carried out in order to examine specific cognitive mechanisms involved in this disruption. Standardized experimental paradigms were used to examine attentional function and working memory capacity in 30 women with FMS and 30 matched controls. ⋯ These findings point to disrupted working memory as a specific mechanism that is disrupted in this population. The results of this study suggest that pain in FMS may play an important role in cognitive disruption. It is likely that many factors, including disrupted cognition, play a role in the reduced quality of life reported by individuals with FMS.
-
The glial cytokine, interleukin-1beta (IL-1beta), potentiates the excitability of nociceptive trigeminal ganglion (TRG) neurons via membrane depolarization following peripheral inflammation. Perforated patch-clamp technique was used this study to show that the mechanism underlying the excitability of small-diameter TRG neurons following inflammation is due to IL-1beta. Inflammation was induced by injection of complete Freund's adjuvant (CFA) into the whisker pad. ⋯ IL-1beta inhibited I(A) to a significantly greater extent than I(K). These results suggest that the inhibitory effect of I(A) and I(K) currents by IL-1beta in small-diameter TRG neurons potentiates neuronal excitability thereby contributing to trigeminal inflammatory hyperalgesia. These findings provide evidence for the development of voltage-gated K(+) channel openers and IL-1beta antagonists as therapeutic agents for the treatment of trigeminal inflammatory hyperalgesia.